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1

Synthesis and Structure of Sr3GaN3 and Sr6GaN5:? Strontium Gallium Nitrides with Isolated Planar [GaN3]6- Anions  

Science Journals Connector (OSTI)

Synthesis and Structure of Sr3GaN3 and Sr6GaN5:? Strontium Gallium Nitrides with Isolated Planar [GaN3]6- Anions ... 9-19 In most cases, an alkaline earth metal is introduced into a Na melt to enhance the solubility of nitrogen, and is incorporated in the nitride product. ... The container was sealed by welding its open end in an argon atmosphere with active water-cooling so that NaN3 did not decompose due to heating during the welding. ...

Dong Gon Park; Zoltįn A. Gįl; Francis J. DiSalvo

2003-02-13T23:59:59.000Z

2

Light-Emitting Diodes on Semipolar Bulk Gallium Nitride Substrate  

Broader source: Energy.gov [DOE]

This project is producing high-efficiency semipolar light-emitting diodes (LEDs) on low-defect bulk gallium nitride (GaN) substrates.

3

P-type gallium nitride  

DOE Patents [OSTI]

Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5{times}10{sup 11} /cm{sup 3} and hole mobilities of about 500 cm{sup 2} /V-sec, measured at 250 K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al. 9 figs.

Rubin, M.; Newman, N.; Fu, T.; Ross, J.; Chan, J.

1997-08-12T23:59:59.000Z

4

Gallium nitride junction field-effect transistor  

DOE Patents [OSTI]

An all-ion implanted gallium-nitride (GaN) junction field-effect transistor (JFET) and method of making the same. Also disclosed are various ion implants, both n- and p-type, together with or without phosphorous co-implantation, in selected III-V semiconductor materials.

Zolper, John C. (Albuquerque, NM); Shul, Randy J. (Albuquerque, NM)

1999-01-01T23:59:59.000Z

5

Gallium nitride junction field-effect transistor  

DOE Patents [OSTI]

An ion implanted gallium-nitride (GaN) junction field-effect transistor (JFET) and method of making the same are disclosed. Also disclosed are various ion implants, both n- and p-type, together with or without phosphorus co-implantation, in selected III-V semiconductor materials. 19 figs.

Zolper, J.C.; Shul, R.J.

1999-02-02T23:59:59.000Z

6

Doping of gallium nitride using disilane  

Science Journals Connector (OSTI)

Keywords: disilane, gallium nitride, metalorganic chemical vapor deposition, organometallic vapor phase epitaxy, silicon doping

A. E. Wickenden; L. B. Rowland; K. Doverspike; D. K. Gaskill; J. A. Freitas, Jr.; D. S. Simons; P. H. Chi

1995-11-01T23:59:59.000Z

7

Effect of the nitrogen ion energy on the MBE growth of thin gallium nitride films  

Science Journals Connector (OSTI)

The influence of the energy of bombarding nitrogen ions on the growth of thin gallium nitride (GaN) films under molecular beam epitaxy (MBE) conditions has been simulated using the method of balance kinetic eq...

D. V. Kulikov; Yu. V. Trushin; V. S. Kharlamov

2010-03-01T23:59:59.000Z

8

Neutron detection using boron gallium nitride semiconductor material  

SciTech Connect (OSTI)

In this study, we developed a new neutron-detection device using a boron gallium nitride (BGaN) semiconductor in which the B atom acts as a neutron converter. BGaN and gallium nitride (GaN) samples were grown by metal organic vapor phase epitaxy, and their radiation detection properties were evaluated. GaN exhibited good sensitivity to ?-rays but poor sensitivity to ?-rays. Moreover, we confirmed that electrons were generated in the depletion layer under neutron irradiation. This resulted in a neutron-detection signal after ?-rays were generated by the capture of neutrons by the B atoms. These results prove that BGaN is useful as a neutron-detecting semiconductor material.

Atsumi, Katsuhiro [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561 (Japan); Inoue, Yoku; Nakano, Takayuki, E-mail: ttnakan@ipc.shizuoka.ac.jp [Department of Electrical and Materials Science, Graduate School of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561 (Japan); Mimura, Hidenori; Aoki, Toru [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8011 (Japan)

2014-03-01T23:59:59.000Z

9

Simulation studies on the evolution of gallium nitride on a liquid gallium surface under plasma bombardmenta)  

Science Journals Connector (OSTI)

Monte Carlo simulations were conducted to study the formation of gallium-nitride (GaN) layer on liquid gallium (Ga) sputtering target immersed in nitrogen ( N 2 ) plasma. In the simulation model N ions were assumed to possess energy equal to the bias voltage applied to the sputtering target with respect to the plasma. The results showed the surface morphology of GaN changed from a relatively smooth GaN on Ga surface at 50 eV N ion energy to a rough surface with GaN dendrites on liquid Ga at 500 eV ion energy. Further increase in N ion energy up to 1 keV resulted in smaller density of GaN dendrites on surface. Increasing surface coverage of Ga by GaN substantially reduced the sputtering yield of Ga from the target. These simulation results were correlated with previously reported experimental observations on liquid Ga surface immersed in the nitrogen plasma of a plasma-sputter-type ion source.

M. R. Vasquez Jr.; R. E. Flauta; M. Wada

2008-01-01T23:59:59.000Z

10

Gallium Nitride Synthesis Using Lithium Metal as a Nitrogen Fixant  

Science Journals Connector (OSTI)

This present work centers on the synthesis of white, microcrystalline gallium nitride from gallium and ammonia, using lithium to increase the solubility of nitrogen-containing species in the metal phase. ... After the acid was decanted and the product was rinsed repeatedly with water and then acetone, the resulting white powder was found to exhibit the powder X-ray diffractogram (PXRD) (Figure 2a) of crystalline gallium nitride (1). ...

Seįn T. Barry; Stephen A. Ruoff; Arthur L. Ruoff

1998-08-13T23:59:59.000Z

11

Carrier localization in gallium nitride  

SciTech Connect (OSTI)

In wide bandgap GaN, a large number of interesting and important scientific questions remain to be answered. For example, the large free electron concentration reaching 10{sup 19} to 10{sup 20} cm{sup - 3} in nominally undoped material are ascribed to intrinsic defects because no chemical impurity has been found at such high concentrations. According to theoretical models, a nitrogen vacancy acts as a donor but its formation energy is very large in n-type materials, making this suggestion controversial. We have investigated the nature of this yet unidentified donor at large hydrostatic pressure. Results from infrared reflection and Raman scattering indicate strong evidence for localization of free carriers by large pressures. The carrier density is drastically decreased by two orders of magnitude between 20 and 30 GPa. Several techniques provide independent evidence for results in earlier reports and present the first quantitative analysis. A possible interpretation of this effect in terms of the resonant donor level is presented.

Wetzel, C. [Lawrence Berkeley National Lab., CA (United States)][California Univ., Berkeley, CA (United States); Walukiewicz, W. [Lawrence Berkeley National Lab., CA (United States); Haller, E.E. [Lawrence Berkeley National Lab., CA (United States)][California Univ., Berkeley, CA (United States)] [and others

1996-09-01T23:59:59.000Z

12

Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films  

E-Print Network [OSTI]

of the Nitrides of Aluminum and Gallium," J. Electrochem.1) 24 (1962). G. Long and L. M. Foster, "Aluminum Nitride, aRefractory for Aluminum to 2000°C," J. Am. Ceram. Soc. ,

Tao, Jonathan Huai-Tse

2010-01-01T23:59:59.000Z

13

Formation of Hollow Gallium Nitride Spheres via Silica Sphere Templates  

Science Journals Connector (OSTI)

Formation of Hollow Gallium Nitride Spheres via Silica Sphere Templates ... To form reasonably uniform gallium oxide shells, the amounts of urea and water added to the reaction mixture were varied. ... Due to the low solubility of urea in 2-propanol, addition of a larger amount of urea than that used in this study is not desirable. ...

Chun-Neng Lin; Michael H. Huang

2008-12-30T23:59:59.000Z

14

IIl-nitride nanowires and heterostructures : growth and optical properties on nanoscale  

E-Print Network [OSTI]

Gallium nitride (GaN) and indium gallium nitride (InGaN) nanowires promise potential for further improving the electricity-to-light energy conversion efficiencies in light emitting diodes due to strain relaxation, reduced ...

Zhou, Xiang, Ph. D. Massachusetts Institute of Technology

2014-01-01T23:59:59.000Z

15

Electronic properties of gallium nitride nanowires  

E-Print Network [OSTI]

This thesis presents a systematic study of the electrical transport in GaN nanowires. Particularly, the effect of the surrounding dielectric on the conductivity of GaN nanowires is experimentally shown for the first time. ...

Yoon, Joonah

2008-01-01T23:59:59.000Z

16

More Efficient Power Conversion for EVs: Gallium-Nitride Advanced Power Semiconductor and Packaging  

SciTech Connect (OSTI)

Broad Funding Opportunity Announcement Project: Delphi is developing power converters that are smaller and more energy efficient, reliable, and cost-effective than current power converters. Power converters rely on power transistors which act like a very precisely controlled on-off switch, controlling the electrical energy flowing through an electrical circuit. Most power transistors today use silicon (Si) semiconductors. However, Delphi is using semiconductors made with a thin layer of gallium-nitride (GaN) applied on top of the more conventional Si material. The GaN layer increases the energy efficiency of the power transistor and also enables the transistor to operate at much higher temperatures, voltages, and power-density levels compared to its Si counterpart. Delphi is packaging these high-performance GaN semiconductors with advanced electrical connections and a cooling system that extracts waste heat from both sides of the device to further increase the device’s efficiency and allow more electrical current to flow through it. When combined with other electronic components on a circuit board, Delphi’s GaN power transistor package will help improve the overall performance and cost-effectiveness of HEVs and EVs.

None

2010-02-01T23:59:59.000Z

17

Femtosecond laser-ultrasonic investigation of plasmonic fields on the metal/gallium nitride interface  

Science Journals Connector (OSTI)

By using femtosecond laser-ultrasonic we demonstrate an approach to study the surface plasmon field optically excited in the interface between metal and a semiconductor thin film. By femtosecond impulsive excitation on gallium–nitride (GaN) different optical probe signals were observed when the impulse-excited nanoacoustic pulse propagated through the metalfilm and metal nanoslits. By analyzing the shape and temporal response of thus induced acousto-optical signals our femtosecond laser-ultrasonic study not only reveals the plasmonic field distribution optically excited in the metal/substrate interface but also confirms that the penetration depth of surface plasmon field into the substrate agrees well with a simulation result.

Hung-Pin Chen; Yu-Chieh Wen; Yi-Hsin Chen; Cheng-Hua Tsai; Kuang-Li Lee; Pei-Kuen Wei; Jinn-Kong Sheu; Chi-Kuang Sun

2010-01-01T23:59:59.000Z

18

The influence of prestrained metalorganic vapor phase epitaxial gallium-nitride templates on hydride vapor phase epitaxial growth  

Science Journals Connector (OSTI)

We have varied the strain situation in metalorganic vapor phase epitaxial (MOVPE) grown gallium-nitride (GaN) by exchanging the nucleation layer and by inserting a submono-Si x N y -interlayer in the first few hundred nanometers of growth on sapphire substrates. The influence on the MOVPE template and subsequent hydride vapor phase epitaxial (HVPE) growth could be shown by in-situ measurements of the sample curvature. Using the results of these investigations we have established a procedure to confine the curvature development in MOVPE and HVPE growth to a minimum. By increasing the layer thickness in HVPE we could create self-separated freestanding GaN layers with small remaining curvature.

2014-01-01T23:59:59.000Z

19

Wet Chemical Functionalization of III–V Semiconductor Surfaces: Alkylation of Gallium Arsenide and Gallium Nitride by a Grignard Reaction Sequence  

Science Journals Connector (OSTI)

Wet Chemical Functionalization of III–V Semiconductor Surfaces: Alkylation of Gallium Arsenide and Gallium Nitride by a Grignard Reaction Sequence ... These observations are consistent with the known solubility of oxidized As species in water. ... Remote H plasma exposure was effective for removing halogens and hydrocarbons from the surfaces of both nitrides at 450 °C, but was not efficient for oxide removal. ...

Sabrina L. Peczonczyk; Jhindan Mukherjee; Azhar I. Carim; Stephen Maldonado

2012-02-28T23:59:59.000Z

20

Effect of substrate temperature on crystal orientation and residual stress in radio frequency sputtered gallium–nitride films  

Science Journals Connector (OSTI)

The crystal orientation and residual stress in gallium nitride(GaN)filmsdeposited on a single-crystal (0001) sapphire substrate using a sputtering system are examined through x-ray diffraction measurements as part of a study of low-temperaturesputtering techniques for GaN. The rf sputtering system has an isolated deposition chamber to prevent contamination with impurities and is expected to produce high-purity nitride films.GaNfilms are deposited at various substrate temperatures and constant gas pressure and input power. This system is found to produce GaNfilms with good crystal orientation with the c axes of GaN crystals oriented normal to the substrate surface. The crystal size of filmsdeposited at high temperature is larger than that deposited at low T s . All films except that deposited at 973 K exhibit compressive residual stress and this residual stress is found to decrease with increasing temperature. Finally the filmdeposited at 973 K was tinged with white and the surface contained numerous microcracks.

Kazuya Kusaka; Takao Hanabusa; Kikuo Tominaga; Noriyoshi Yamauchi

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Identification of the gallium vacancy-oxygen pair defect in GaN  

SciTech Connect (OSTI)

Cation vacancies like V{sub Ga}, V{sub Al} and their complexes with oxygen are predicted to be abundant in III-nitrides and to play an important role in nonradiative recombination. Appearing in triple or double negatively charged states, they are not paramagnetic and have not so far been detected by magnetic resonance even under illumination. In this Brief Report, we demonstrate an efficient way to make cation vacancy defects in GaN detectable by electron paramagnetic resonance and present our identification of the V{sub Ga}O{sub N} pair in GaN which is the model material for the III-nitrides and their alloys.

Son, N. T.; Hemmingsson, C. G.; Janzen, E. [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden); Paskova, T.; Evans, K. R. [Kyma Technologies Inc., 8829 Midway West Road, Raleigh, North Carolina 27617 (United States); Usui, A. [R and D Division, Furukawa Co., Ltd., Tsukuba, Ibaraki 305-0856 (Japan); Morishita, N.; Ohshima, T. [Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Isoya, J. [Graduate School of Library, Information and Media Studies, University of Tsukuba, Tsukuba, Ibaraki 305-8550 (Japan); Monemar, B. [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden); Nanometer Structure Consortium, Lund University, P.O. Box 118, S-221 00 Lund (Sweden)

2009-10-15T23:59:59.000Z

22

High-Quality, Low-Cost Bulk Gallium Nitride Substrates  

Broader source: Energy.gov [DOE]

To develop ESG into a viable bulk growth process for GaN that is more scalable to large-area wafer manufacturing and able to produce cost-effective, high-quality bulk GaN substrates.

23

Nanostructural engineering of nitride nucleation layers for GaN substrate dislocation reduction.  

SciTech Connect (OSTI)

With no lattice matched substrate available, sapphire continues as the substrate of choice for GaN growth, because of its reasonable cost and the extensive prior experience using it as a substrate for GaN. Surprisingly, the high dislocation density does not appear to limit UV and blue LED light intensity. However, dislocations may limit green LED light intensity and LED lifetime, especially as LEDs are pushed to higher current density for high end solid state lighting sources. To improve the performance for these higher current density LEDs, simple growth-enabled reductions in dislocation density would be highly prized. GaN nucleation layers (NLs) are not commonly thought of as an application of nano-structural engineering; yet, these layers evolve during the growth process to produce self-assembled, nanometer-scale structures. Continued growth on these nuclei ultimately leads to a fully coalesced film, and we show in this research program that their initial density is correlated to the GaN dislocation density. In this 18 month program, we developed MOCVD growth methods to reduce GaN dislocation densities on sapphire from 5 x 10{sup 8} cm{sup -2} using our standard delay recovery growth technique to 1 x 10{sup 8} cm{sup -2} using an ultra-low nucleation density technique. For this research, we firmly established a correlation between the GaN nucleation thickness, the resulting nucleation density after annealing, and dislocation density of full GaN films grown on these nucleation layers. We developed methods to reduce the nuclei density while still maintaining the ability to fully coalesce the GaN films. Ways were sought to improve the GaN nuclei orientation by improving the sapphire surface smoothness by annealing prior to the NL growth. Methods to eliminate the formation of additional nuclei once the majority of GaN nuclei were developed using a silicon nitride treatment prior to the deposition of the nucleation layer. Nucleation layer thickness was determined using optical reflectance and the nucleation density was determined using atomic force microscopy (AFM) and Nomarski microscopy. Dislocation density was measured using X-ray diffraction and AFM after coating the surface with silicon nitride to delineate all dislocation types. The program milestone of producing GaN films with dislocation densities of 1 x 10{sup 8} cm{sup -2} was met by silicon nitride treatment of annealed sapphire followed by the multiple deposition of a low density of GaN nuclei followed by high temperature GaN growth. Details of this growth process and the underlying science are presented in this final report along with problems encountered in this research and recommendations for future work.

Koleske, Daniel David; Lee, Stephen Roger; Lemp, Thomas Kerr; Coltrin, Michael Elliott; Cross, Karen Charlene; Thaler, Gerald

2009-07-01T23:59:59.000Z

24

Neutron irradiation effects on gallium nitride-based Schottky diodes  

SciTech Connect (OSTI)

Depth-resolved cathodoluminescence spectroscopy (DRCLS), time-resolved surface photovoltage spectroscopy, X-ray photoemission spectroscopy (XPS), and current-voltage measurements together show that fast versus thermal neutrons differ strongly in their electronic and morphological effects on metal-GaN Schottky diodes. Fast and thermal neutrons introduce GaN displacement damage and native point defects, while thermal neutrons also drive metallurgical reactions at metal/GaN interfaces. Defect densities exhibit a threshold neutron fluence below which thermal neutrons preferentially heal versus create new native point defects. Scanning XPS and DRCLS reveal strong fluence- and metal-dependent electronic and chemical changes near the free surface and metal interfaces that impact diode properties.

Lin, Chung-Han; Katz, Evan J.; Zhang, Zhichun [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States)] [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States); Qiu, Jie; Cao, Lei [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)] [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Mishra, Umesh K. [Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of California, Santa Barbara, California 93106 (United States)] [Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of California, Santa Barbara, California 93106 (United States); Brillson, Leonard J. [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States) [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States); Department of Physics and Center for Materials Research, The Ohio State University, Columbus, Ohio 43210 (United States)

2013-10-14T23:59:59.000Z

25

Polythiophene-based charge dissipation layer for electron beam lithography of zinc oxide and gallium nitride  

Science Journals Connector (OSTI)

The ability of thin polythiophene layers to dissipate accumulated charge in the electron beam lithography (EBL) of wide bandgap semiconductors such as zinc oxide and gallium nitride is demonstrated. A quick and inexpensive processing method is demonstrated for EBL exposure of dense and high-resolution patterns in a hydrogen silsesquioxane (HSQ) negative-tone resistdeposited on bulk ZnO samples and with GaN/AlN on sapphire substrates. For the former experimental results are given for three different cases: where no charge dissipation layer was used as well as cases where 40-nm-thick Al and 100-nm-thick conductive polymer layers were used on the top of the HSQ resist. For the latter material EBL exposure was investigated for pure HSQ and for HSQ with a thin conductive polymer layer on top. Based on the scanning electron microscope observations of the resulting photonic crystal(PhC) pattern conventional Al and the proposed polymer approach were compared. Good agreement between these results is reported while the new method considerably simplifies sample processing. Spin-coatable conducting polymer may be easily removed due to its solubility in water which makes it a perfect solution for the processing of amphoteric oxide samples i.e. zinc oxide. Gallium nitride processing also benefits from polymer dissipation layer usage due to extended exposure range and the avoidance of dense pattern overexposure in HSQ.

R. Dylewicz; S. Lis; R. M. De La Rue; F. Rahman

2010-01-01T23:59:59.000Z

26

The reaction of carbon tetrachloride with gallium arsenide ,,001... L. Li., S, Gan, B.-K. Han, H. Qi, and R. F. Hicksa)  

E-Print Network [OSTI]

The reaction of carbon tetrachloride with gallium arsenide ,,001... L. Li., S, Gan, B.-K. Han, H, California 90095 Received 26 June 1997; accepted for publication 30 December 1997 Carbon tetrachloride of steps during the vapor-phase epitaxial growth of IIIĀ­V compound semiconductors.3,4 Carbon tetrachloride

Li, Lian

27

Imaging the p-n junction in a gallium nitride nanowire with a scanning microwave microscope  

SciTech Connect (OSTI)

We used a broadband, atomic-force-microscope-based, scanning microwave microscope (SMM) to probe the axial dependence of the charge depletion in a p-n junction within a gallium nitride nanowire (NW). SMM enables the visualization of the p-n junction location without the need to make patterned electrical contacts to the NW. Spatially resolved measurements of S{sub 11}{sup ?}, which is the derivative of the RF reflection coefficient S{sub 11} with respect to voltage, varied strongly when probing axially along the NW and across the p-n junction. The axial variation in S{sub 11}{sup ?}? effectively mapped the asymmetric depletion arising from the doping concentrations on either side of the junction. Furthermore, variation of the probe tip voltage altered the apparent extent of features associated with the p-n junction in S{sub 11}{sup ?} images.

Imtiaz, Atif [Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309 (United States); Wallis, Thomas M.; Brubaker, Matt D.; Blanchard, Paul T.; Bertness, Kris A.; Sanford, Norman A.; Kabos, Pavel, E-mail: kabos@boulder.nist.gov [Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Weber, Joel C. [Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309 (United States); Coakley, Kevin J. [Information Technology Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

2014-06-30T23:59:59.000Z

28

Synthesis, morphology and optical properties of GaN and AlGaN semiconductor nanostructures  

SciTech Connect (OSTI)

Hexagonal Gallium Nitride (GaN) and Aluminum Gallium Nitride (AlGaN) nanoparticles were synthesized by sol-gel method using Ethylene Diamine Tetra Acetic acid (EDTA) complex route. Powder X-ray diffraction (PXRD) analysis confirms the hexagonal wurtzite structure of GaN and Al{sub 0.25}Ga{sub 0.75}N nanoparticles. Surface morphology and elemental analysis were carried out by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDX). The room temperature Photoluminescence (PL) study shows the near band edge emission for GaN at 3.35 eV and at 3.59 eV for AlGaN nanoparticles. The Aluminum (Al) composition of 20% has been obtained from PL emission around 345 nm.

Kuppulingam, B., E-mail: drbaskar2009@gmail.com; Singh, Shubra, E-mail: drbaskar2009@gmail.com; Baskar, K., E-mail: drbaskar2009@gmail.com [Crystal Growth Centre, Anna University, Chennai-600025 (India)

2014-04-24T23:59:59.000Z

29

Self-Assembled Monolayers of Alkylphosphonic Acid on GaN Substrates  

Science Journals Connector (OSTI)

In addition to their applications for short-wavelength optoelectronic and high-power electronics, group III nitrides (AlN, GaN, and InN) have been employed as components of chemical and biological sensors for gas and solution samples. ... (27) In the basic solution, ?water decreased quickly to reach a smaller plateau value, probably reflecting the electrostatic repulsion between the deprotonated ODPA and negatively charged gallium oxide surface(46) in addition to the higher solubility of deprotonated ODPA in more basic solution. ... Gallium nitride is a wide band gap semiconductor that demonstrates a unique set of optical and electrical properties as well as aqueous stability and biocompatibility. ...

Takashi Ito; Sarah M. Forman; Chundi Cao; Feng Li; Charles R. Eddy, Jr.; Michael A. Mastro; Ronald T. Holm; Richard L. Henry; Keith L. Hohn; J. H. Edgar

2008-06-04T23:59:59.000Z

30

Lewis Base Adduct Stabilized Organogallium Azides:? Synthesis and Dynamic NMR Spectroscopic Studies of Novel Precursors to Gallium Nitride and Role of Ammonia as Reactive Carrier Gas  

Science Journals Connector (OSTI)

Lewis Base Adduct Stabilized Organogallium Azides:? Synthesis and Dynamic NMR Spectroscopic Studies of Novel Precursors to Gallium Nitride and Role of Ammonia as Reactive Carrier Gas ... Solvents were dried under argon according to standard methods; n-pentane and toluene were stored over Na/K alloy, and diethyl ether and thf over potassium benzophenoate (residual water solubility in other solvents than thf. ...

Alexander Miehr; Mike R. Mattner; Roland A. Fischer

1996-04-16T23:59:59.000Z

31

Growth of Core?Shell Ga?GaN Nanostructures via a Conventional Reflux Method and the Formation of Hollow GaN Spheres  

Science Journals Connector (OSTI)

Gallium nitride (GaN) is an important III?V semiconductor with a wide direct band gap of ?3.4 eV. ... LiHMDS exhibits good solubility in TOA. ... The products were collected by centrifugation twice at 7000 rpm for 2 min in hexane, isopropanol, ethanol, and then deionized water. ...

Tz-Jun Kuo; Chi-Liang Kuo; Chun-Hong Kuo; Michael H. Huang

2009-02-05T23:59:59.000Z

32

Radiation-Hardened Gallium Nitride Detector and Arrays for Fusion Diagnostics  

SciTech Connect (OSTI)

This poster reports testing to confirm that GaN devices exhibit the extreme radiation hardness needed for use at the NIF, functioning properly after 1x10{sup 12} protons/cm{sup 2} proton irradiation in one year.

Sun, K. X., and MacNeil, L.

2011-09-08T23:59:59.000Z

33

Control of the emission wavelength of gallium nitride-based nanowire light-emitting diodes.  

E-Print Network [OSTI]

??Halbleiter-Nanosäulen (auch -Nanodrähte) werden als Baustein für Leuchtdioden (LEDs) untersucht. Herkömmliche LEDs aus Galliumnitrid (GaN) bestehen aus mehreren Kristallschichten auf einkristallinen Substraten. Ihr Leistungsvermögen wird… (more)

Wölz, Martin

2013-01-01T23:59:59.000Z

34

E-Print Network 3.0 - arsenide gallium nitride Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

An advanced diffusion model to identify emergent research issues: the case of optoelectronic devices Summary: instrumentation Absorption coefficients Aluminium Nitrides Aluminium...

35

Nucleation and Growth of GaN on GaAs (001) Substrates  

SciTech Connect (OSTI)

The nucleation of GaN thin films on GaAs is investigated for growth at 620 "C. An rf plasma cell is used to generate chemically active nitrogen from N2. An arsenic flux is used in the first eight monolayer of nitride growth to enhance nucleation of the cubic phase. Subsequent growth does not require an As flux to preserve the cubic phase. The nucleation of smooth interfaces and GaN films with low stacking fault densities is dependent upon relative concentrations of active nitrogen species in the plasma and on the nitrogen to gallium flux ratio.

Drummond, Timothy J.; Hafich, Michael J.; Heller, Edwin J.; Lee, Stephen R.; Liliental-Weber, Zuzanna; Ruvimov, Sergei; Sullivan, John P.

1999-05-03T23:59:59.000Z

36

Structure and electronic properties of saturated and unsaturated gallium nitride nanotubes  

SciTech Connect (OSTI)

The atomic and electronic structures of saturated and unsaturated GaN nanotubes along the [001] direction with (100) lateral facets are studied using first-principles calculations. Atomic relaxation of nanotubes shows that appreciable distortion occurs in the unsaturated nanotubes. All the nanotubes considered, including saturated and unsaturated ones, exhibit semiconducting, with a direct band gap. Surface states arisen from the threefold-coordinated N and Ga atoms at the lateral facets exist inside the bulk-like band gap. When the nanotubes saturated with hydrogen, these dangling bond bands are removed from the band gap, but the band gap decreases with increasing the wall thickness of the nanotubes.

Wang, Zhiguo; Wang, Shengjie; Li, Jingbo; Gao, Fei; Weber, William J.

2009-11-05T23:59:59.000Z

37

Picosecond response of gallium-nitride metal–semiconductor–metal photodetectors  

Science Journals Connector (OSTI)

Metal–semiconductor–metal ultraviolet photodiodes fabricated on GaN were tested in the picosecond regime with an electro-optic sampling system. A device with a feature size of 1 ?m showed a response with 1.4 ps rise time and 3.5 ps full width at half maximum. The derived electron velocity 1.43×10 7 ? cm/s is in good agreement with independent photoexcitation measurements. A slower impulse response was observed in a device with smaller feature size of 0.5?? m .

Jianliang Li; Ying Xu; T. Y. Hsiang; W. R. Donaldson

2004-01-01T23:59:59.000Z

38

Group III-nitride thin films grown using MBE and bismuth  

DOE Patents [OSTI]

The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

Kisielowski, Christian K. (Peidmont, CA); Rubin, Michael (Berkeley, CA)

2000-01-01T23:59:59.000Z

39

Group III-nitride thin films grown using MBE and bismuth  

DOE Patents [OSTI]

The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

Kisielowski, Christian K. (Piedmont, CA); Rubin, Michael (Berkeley, CA)

2002-01-01T23:59:59.000Z

40

Physics based analytical modelling of Gallium Nitride(GaN) MESFET considering different ion implantation energy with high temperature annealing.  

E-Print Network [OSTI]

??A physics based analytical model of ion implanted GaN MESFET has been presented considering high temperature annealing effects. Choosing appropriate activation energy of impurity atoms,… (more)

Raghavan, Vinay

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Photopolymerization of Self-Assembled Monolayers of Diacetylenic Alkylphosphonic Acids on Group-III Nitride Substrates  

Science Journals Connector (OSTI)

(1, 4-7) In addition, the selectivity and sensitivity of a nitrides-based sensor can be tailored by modifying the nitride’s surface with a thin layer that selectively recognizes chemical species of interest. ... However, ODPA SAMs desorbed from GaN substrates upon immersion in aqueous solution, especially in basic solution, probably reflecting the high solubility of deprotonated ODPA in the solution,(18) electrostatic repulsion between the negatively charged ODPA and substrate surface,(18) and/or the dissolution of the gallium oxide layer. ... Water contact angles on group-III nitride samples were measured using a PG-1 pocket contact angle goniometer by reading contact angle values of the two sides of a drop (2 ?L) within 30 s after deposition of the drop. ...

Feng Li; Evgeniy Shishkin; Michael A. Mastro; Jennifer K. Hite; Charles R. Eddy, Jr.; J. H. Edgar; Takashi Ito

2010-06-04T23:59:59.000Z

42

Comparative band alignment of plasma-enhanced atomic layer deposited high-k dielectrics on gallium nitride  

SciTech Connect (OSTI)

Al{sub 2}O{sub 3} films, HfO{sub 2} films, and HfO{sub 2}/Al{sub 2}O{sub 3} stacked structures were deposited on n-type, Ga-face, GaN wafers using plasma-enhanced atomic layer deposition (PEALD). The wafers were first treated with a wet-chemical clean to remove organics and an in-situ combined H{sub 2}/N{sub 2} plasma at 650 Degree-Sign C to remove residual carbon contamination, resulting in a clean, oxygen-terminated surface. This cleaning process produced slightly upward band bending of 0.1 eV. Additional 650 Degree-Sign C annealing after plasma cleaning increased the upward band bending by 0.2 eV. After the initial clean, high-k oxide films were deposited using oxygen PEALD at 140 Degree-Sign C. The valence band and conduction band offsets (VBOs and CBOs) of the Al{sub 2}O{sub 3}/GaN and HfO{sub 2}/GaN structures were deduced from in-situ x-ray and ultraviolet photoemission spectroscopy (XPS and UPS). The valence band offsets were determined to be 1.8 and 1.4 eV, while the deduced conduction band offsets were 1.3 and 1.0 eV, respectively. These values are compared with the theoretical calculations based on the electron affinity model and charge neutrality level model. Moreover, subsequent annealing had little effect on these offsets; however, the GaN band bending did change depending on the annealing and processing. An Al{sub 2}O{sub 3} layer was investigated as an interfacial passivation layer (IPL), which, as results suggest, may lead to improved stability, performance, and reliability of HfO{sub 2}/IPL/GaN structures. The VBOs were {approx}0.1 and 1.3 eV, while the deduced CBOs were 0.6 and 1.1 eV for HfO{sub 2} with respect to Al{sub 2}O{sub 3} and GaN, respectively.

Yang Jialing; Eller, Brianna S.; Zhu Chiyu; England, Chris; Nemanich, Robert J. [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States)

2012-09-01T23:59:59.000Z

43

E-Print Network 3.0 - adaptive nitride-based coatings Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

DELAUSANNE Summary: AND ELECTRONICS PROF. N. GRANDJEAN 33 III-NITRIDE BASED OPTOELECTRONIC DEVICES 34 GALLIUM NITRIDE-BASED 2D... FOR DIVERSE APPLICATIONS 84 HOLE ARRAY...

44

Temperature dependence of electrical properties of gallium-nitride bulk single crystals doped with Mg and their evolution with annealing  

Science Journals Connector (OSTI)

Comprehensive studies of the electrical properties of Mg-doped bulk GaN crystals grown by high-pressure synthesis were performed as a function of temperature up to 750?°C. Annealing of the samples in nitrogen ambient modifies qualitatively their resistivity values ? and the ?(T) variation. It was found that our material is characterized by a high concentration of oxygen-related donors and that the charge transport in the studied samples is determined by two types of states one of shallow character (Mg-related state E A ?0.15? eV ) and the second one much more deep E 2 ?0.95? eV (above the valence band). Depending on the effective concentration of either states different resistivities ? can be observed: lower resistivity (?10 6 ??? cm at ambient temperature) in samples with dominant E 2 states. For the first type of samples annealing at T ann <500?° C leads to a decrease of their resistivity and is associated with an increase of the effective concentration of the shallow Mg acceptors. Annealing of both types of samples at temperatures between 600 and 750?°C leads to an increase of the deep state concentration. The presence of hydrogen ambient during annealing of the low-resistivity samples strongly influences their properties. The increase of the sample resistivity and an appearance of a local vibrational mode of hydrogen at 3125 cm?1 were observed. These effects can be removed by annealing in hydrogen-free ambient.

E. Litwin-Staszewska; T. Suski; R. Piotrzkowski; I. Grzegory; M. Bockowski; J. L. Robert; L. Ko?czewicz; D. Wasik; E. Kami?ska; D. Cote; B. Clerjaud

2001-01-01T23:59:59.000Z

45

Efficient Switches for Solar Power Conversion: Four Quadrant GaN Switch Enabled Three Phase Grid-Tied Microinverters  

SciTech Connect (OSTI)

Solar ADEPT Project: Transphorm is developing power switches for new types of inverters that improve the efficiency and reliability of converting energy from solar panels into useable electricity for the grid. Transistors act as fast switches and control the electrical energy that flows in an electrical circuit. Turning a transistor off opens the circuit and stops the flow of electrical current; turning it on closes the circuit and allows electrical current to flow. In this way a transistor can be used to convert DC from a solar panel into AC for use in a home. Transphorm’s transistors will enable a single semiconductor device to switch electrical currents at high-voltage in both directions—making the inverter more compact and reliable. Transphorm is using Gallium Nitride (GaN) as a semiconductor material in its transistors instead of silicon, which is used in most conventional transistors, because GaN transistors have lower losses at higher voltages and switching frequencies.

None

2012-02-13T23:59:59.000Z

46

Analyse og konstruksjon av en klasse B effektforsterker i GaN teknologi; Class B power amplifier design with GaN technology.  

E-Print Network [OSTI]

??De senere årene har vist en stadig ųkende interesse for transistorer basert på GalliumNitrid, spesielt i design av effektforsterkere for trådlųse applikasjoner. Denne rapportenbeskriver to… (more)

Mogstad, Einar Berge

2010-01-01T23:59:59.000Z

47

Characterization of GaN nanowires grown on PSi, PZnO and PGaN on Si (111) substrates by thermal evaporation  

SciTech Connect (OSTI)

In this research, we used an easy and inexpensive method to synthesize highly crystalline GaN nanowires (NWs); on different substrates such as porous silicon (PSi), porous zinc oxide (PZnO) and porous gallium nitride (PGaN) on Si (111) wafer by thermal evaporation using commercial GaN powder without any catalyst. Micro structural studies by scanning electron microscopy and transmission electron microscope measurements reveal the role of different substrates in the morphology, nucleation and alignment of the GaN nanowires. The degree of alignment of the synthesized nanowires does not depend on the lattice mismatch between wires and their substrates. Further structural and optical characterizations were performed using high resolution X-ray diffraction and energy-dispersive X-ray spectroscopy. Results indicate that the nanowires are of single-crystal hexagonal GaN. The quality and density of grown GaN nanowires for different substrates are highly dependent on the lattice mismatch between the nanowires and their substrates and also on the size of the porosity of the substrates. Nanowires grown on PGaN have the best quality and highest density as compared to nanowires on other substrates. By using three kinds of porous substrates, we are able to study the increase in the alignment and density of the nanowires.

Shekari, Leila; Hassan, Haslan Abu; Thahab, Sabah M.; Hassan, Zainuriah [Nano-Optoelectronics Research and Technology Laboratory School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Materials Engineering Department, College of Engineering, University of Kufa, Najaf (Iraq); Nano-Optoelectronics Research and Technology Laboratory School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

2012-06-20T23:59:59.000Z

48

2009 Minerals Yearbook U.S. Department of the Interior  

E-Print Network [OSTI]

As and gallium nitride (GaN) and was used in integrated circuits (ICs) and optoelectronic devices [laser diodes

49

Transistor-Based Miniature Microwave-Drill Applicator Yehuda Meir and Eli Jerby*  

E-Print Network [OSTI]

. Recent developments of gallium-nitride (GaN) and silicon- carbide (SiC) transistors have increased

Jerby, Eli

50

THERMAL STUDY OF A GaN-BASED HEMT A Dissertation  

E-Print Network [OSTI]

of gallium-nitride (GaN) high-electron-mobility transistors (HEMTs) under bias conditions. An experimental

Sen, Mihir

51

Employment after UC Graduation: 2005 2007: Assistant Professor, Department of Electrical Engineering, California Polytechnic State  

E-Print Network [OSTI]

and Educational Activity on Gallium-Nitride (GaN) Lasers and Light Emitting Diodes (LEDs)" International Journal

Boolchand, Punit

52

High Efficiency m-plane LEDs on Low Defect Density Bulk GaN Substrates  

SciTech Connect (OSTI)

Solid-state lighting is a key technology for reduction of energy consumption in the US and worldwide. In principle, by replacing standard incandescent bulbs and other light sources with sources based on light-emitting diodes (LEDs), ultimate energy efficiency can be achieved. The efficiency of LEDs has improved tremendously over the past two decades, however further progress is required for solid- state lighting to reach its full potential. The ability of an LED at converting electricity to light is quantified by its internal quantum efficiency (IQE). The material of choice for visible LEDs is Gallium Nitride (GaN), which is at the basis of blue-emitting LEDs. A key factor limiting the performance of GaN LEDs is the so-called efficiency droop, whereby the IQE of the LED decreases significantly at high current density. Despite decades of research, efficiency droop remains a major issue. Since high-current operation is necessary for practical lighting applications, reducing droop is a major challenge for the scientific community and the LED industry. Our approach to solving the droop issue is the use of newly available low-defect-density bulk GaN non-polar substrates. In contrast to the standard foreign substrates (sapphire, silicon carbide, silicon) used in the industry, we have employed native bulk GaN substrates with very low defect density, thus ensuring exquisite material quality and high IQE. Whereas all commercial LEDs are grown along the c-plane crystal direction of GaN, we have used m-plane non-polar substrates; these drastically modify the physical properties of the LED and enable a reduction of droop. With this approach, we have demonstrated very high IQE performance and low droop. Our results focused on violet and blue LEDs. For these, we have demonstrated very high peak IQEs and current droops of 6% and 10% respectively (up to a high current density of 200A.cm-2). All these results were obtained under electrical operation. These high IQE and low droop values are in line with the program’s milestones. They demonstrate that bulk non-polar GaN substrates represent a disruptive technology for LED performance. Application of this technology to real-world products is feasible, provided that the cost of GaN substrates is compatible with the market’s requirement.

David, Aurelien

2012-10-15T23:59:59.000Z

53

E-Print Network 3.0 - aluminum oxide selectively Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

between GaN and AlGaN has been observed up to an aluminum mole fraction... oxides.1-3 For gallium nitride and aluminum gallium nitride this effect has been seldom reported.4... ,...

54

Growth of 5 mm GaN Single Crystals at 750 °C from an Na?Ga Melt  

Science Journals Connector (OSTI)

Laser diodes using GaN-based III?V nitrides have been developed, and nitride semiconductor devices are now of considerable interest. ... When the inclusions were exposed to air, they reacted with water vapor in air and produced sodium hydroxide and small gallium metal droplets at the fracture surface of the crystal. ... The solubility of nitrogen in liquid sodium is extremely low (7.1 × 10-9 mol % N at 600 °C). ...

Masato Aoki; Hisanori Yamane; Masahiko Shimada; Seiji Sarayama; Francis J. DiSalvo

2001-02-03T23:59:59.000Z

55

Top-gate thin-film transistors based on GaN channel layer Rongsheng Chen, Wei Zhou, and Hoi Sing Kwok  

E-Print Network [OSTI]

liquid gallium target. The GaN TFTs exhibit good electrical performance such as field effect mobility of 1 cm2 /Vs, threshold voltage of Ć?0.4 V, on/off current ratio of 105 , and subthreshold swing of 0 electrical sta- bility of ZnO-based TFTs is still a main issue preventing from commercialization.9 Bottom

56

Gallium interactions with Zircaloy  

SciTech Connect (OSTI)

This study focuses on the effects of gallium ion implantation into zircaloy cladding material to investigate the effects that gallium may have in a reactor. High fluence ion implantation of Ga ions was conducted on heated Zircaloy-4 in the range of 10{sup 16}--10{sup 18} Ga ions/cm2. Surface effects were studied using SEM and electron microprobe analysis. The depth profile of Ga in the Zircaloy was characterized with Rutherford backscattering and SIMS techniques. Results indicate that the Zirc-4 is little affected up to a fluence of 10{sup 17} Ga ions/cm{sup 2}. After implantation of 10{sup 18} Ga ions/cm{sup 2}, sub-grain features on the order of 2 {micro}m were observed which may be due to intermetallic compound formation between Ga and Zr. For the highest fluence implant, Ga content in the Zirc-4 reached a saturation value of between 30 and 40 atomic %; significant enhanced diffusion was observed but gallium was not seen to concentrate at grain boundaries.

Woods, A.L. [ed.; West, M.K. [Texas A and M Univ., College Station, TX (United States). Dept. of Nuclear Engineering

1999-01-01T23:59:59.000Z

57

Gain analysis of blue nitride-based lasers by small signal modulation  

Science Journals Connector (OSTI)

With a small signal frequency-modulation of the driving current the resonance frequency and the damping factor of the optical output power response of blue nitride-based ridge lasers grown on [0001]-plane gallium-nitride substrates were investigated with a network analyzer setup. From the linear dependence of the squared resonance frequency on the driving current the gain coefficients of the logarithmic gain model could be extracted being 7680 ? cm ? 1 for blue nitride-based lasers. For this purpose additional parameters such as the carrier density and the confinement factor were assigned by carrier lifetime and quantum efficiencymeasurements and one dimensional transfer matrix simulations respectively.

J. Müller; M. Scheubeck; M. Sabathil; G. Brüderl; D. Dini; S. Tautz; T. Lermer; A. Breidenassel; S. Lutgen

2010-01-01T23:59:59.000Z

58

Cyclotron Resonance in Gallium  

Science Journals Connector (OSTI)

Azbel'-Kaner cyclotron resonance has been studied at 36 and 9 Gc/sec at 1.2°K in the three principal symmetry planes of gallium with the microwave currents both parallel and perpendicular to the applied magnetic field. The resonance signals were characterized by extreme complexity and high resolution (long relaxation times). Mass values are determined as a function of orientation of the magnetic field in the sample surfaces. No interpretation of the mass branches on a model Fermi surface is attempted, but some correlations with previous de Haas-van Alphen data are presented.

T. W. Moore

1968-01-15T23:59:59.000Z

59

Gallium interactions with Zircaloy  

E-Print Network [OSTI]

of weapons-grade plutonium (WGPu) in the United States is the conversion of weapons-grade plutonium into mixed-oxide (MOX) reactor fuel. MOX fuel fabricated in this way must be compatible with currently used nuclear fuel components. Since US WGPu contains... that gallium may have on zircaloy cladding during reactor operation. As a result of the reprocessing of spent fuel used in European nuclear programs, many studies have been conducted on the production and behavior of MOX fuel in traditional reactors [5...

West, Michael Keith

2012-06-07T23:59:59.000Z

60

Tunnel MOS Heterostructure Field Effect Transistor for RF Switching Applications  

E-Print Network [OSTI]

. ..................................................................................... 5 Figure 4. The lattices of N-face and Ga-face gallium nitride. .......................................... 10 Figure 5. The lattice constants and bandgaps of III-nitride semiconductors and their alloys... semiconductors and particularly Gallium Nitride (GaN) are gaining a lot of attention for high speed and high power switching applications due to their large critical breakdown electric fields, high mobility and high saturated electron velocity [1, 2]. GaN has...

Rezanezhad Gatabi, Iman

2013-06-06T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Substrate-dependent wetting layer formation during GaN growth: Impact on the morphology of the films  

SciTech Connect (OSTI)

We have compared epitaxial growth of GaN films on 6H-SiC(0001)-({radical}(3)x{radical}(3))R30 deg. -Ga and on (0001)-sapphire. Predeposited Ga layers were nitrided by ion beam assisted molecular beam epitaxy. Whereas on SiC the initially deposited Ga covers the substrate surface completely, on sapphire only Ga droplets are present. The different distribution of the predeposited Ga affects the morphology of GaN significantly. Scanning electron microscopy and atomic force microscopy analysis of the grown films show that the complete wetting of the SiC substrate with Ga enhances finally the size and the flatness of GaN terraces and thus the quality of the film. X-ray photoelectron spectroscopy measurements reveal that metallic Ga resides also on top of the GaN films during the growth.

Sidorenko, A.; Peisert, H.; Neumann, H.; Chasse, T. [Universitaet Tuebingen, Institut fuer Physikalische und Theoretische Chemie, Auf der Morgenstelle 8, D-72076 Tuebingen (Germany); Leibniz-Institut fuer Oberflaechenmodifizierung e.V. Permoserstrasse 15, D-04318 Leipzig (Germany); Universitaet Tuebingen, Institut fuer Physikalische und Theoretische Chemie, Auf der Morgenstelle 8, D-72076 Tuebingen (Germany)

2007-08-15T23:59:59.000Z

62

Loss of Siloxane Monolayers from GaN Surfaces in Water  

Science Journals Connector (OSTI)

Gallium nitride, with a thin passivating layer of Ga2O3, has been functionalized with octadecyltrichlorosilane (OTS) and aminopropyltriethoxysilane (APTES) self-assembled monolayers (SAMs). ... Repeat solubility tests have shown that the time necessary for complete loss of an OTS SAM in pH 7 buffer can vary from 1 to 24 h. ... The powder was found to be soluble in both water and buffer at around 1–10 ppm. ...

Christina Arisio; Catherine A. Cassou; Marya Lieberman

2013-03-27T23:59:59.000Z

63

Metal contacts on ZnSe and GaN  

SciTech Connect (OSTI)

Recently, considerable interest has been focused on the development of blue light emitting materials and devices. The focus has been on GaN and ZnSe, direct band gap semiconductors with bands gaps of 3.4 and 2.6 eV, respectively. To have efficient, reliable devices it is necessary to have thermally and electrically stable Ohmic contacts. This requires knowledge of the metal-semiconductor reaction behavior. To date few studies have investigated this behavior. Much information has accumulated over the years on the behavior of metals on Si and GaAs. This thesis provides new knowledge for the more ionic wide band gap semiconductors. The initial reaction temperatures, first phases formed, and phase stability of Pt, Pd, and Ni on both semiconductors were investigated. The reactions of these metals on ZnSe and GaN are discussed in detail and correlated with predicted behavior. In addition, comparisons are made between these highly ionic semiconductors and Si and GaAs. The trends observed here should also be applicable to other II-VI and III-Nitride semiconductor systems, while the information on phase formation and stability should be useful in the development of contacts for ZnSe and GaN devices.

Duxstad, K.J. [Univ. of California, Berkeley, CA (United States). Materials Science and Mineral Engineering; [Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.

1997-05-01T23:59:59.000Z

64

Au-free Ohmic Contacts to Gallium Nitride and Graphene  

E-Print Network [OSTI]

. ................................................................................................. 43 Figure 28 Specific contact resistivity of co-sputtered Ti-Ta contact calculated after RTA at different temperatures ......................................................... 43 Figure 29 PMMA transfer method for transferring CVD grown...

Ravikirthi, Pradhyumna

2014-08-10T23:59:59.000Z

65

Effect of Gallium Nitride Template Layer Strain on the Growth...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

5µm layer experienced tensile strain. Dynamic Secondary Ion Mass Spectrometry (SIMS) depth profiles show that the 15µm template layer device had an average indium...

66

In situ chemical sensing in AlGaN/GaN high electron mobility transistor metalorganic chemical vapor deposition process for real-time  

E-Print Network [OSTI]

; accepted 14 June 2005; published 18 July 2005 Gallium nitride and its alloys promise to be key materials.1116/1.1993616 I. INTRODUCTION In recent years, gallium-nitride GaN - and aluminum- gallium-nitride AlGaN -based are grown at high temperatures e.g., up to 1100 Ā°C using large concentrations of H2 carrier and NH3 N source

Rubloff, Gary W.

67

Applied Materials Develops an Advanced Epitaxial Growth System to Bring Down LED Costs  

Broader source: Energy.gov [DOE]

With the help of DOE funding, Applied Materials has developed an advanced epitaxial growth system for gallium nitride (GaN) LED devices that decreases operating costs, increases internal quantum efficiency, and improves binning yields.

68

Device-level thermal analysis of GaN-based electronics  

E-Print Network [OSTI]

Gallium nitride (GaN)-based microelectronics are one of the most exciting semiconductor technologies for high power density and high frequency electronics. The excellent electrical properties of GaN and its related alloys ...

Bagnall, Kevin Robert

2013-01-01T23:59:59.000Z

69

Photoluminescence from GaN layers at high temperatures as a candidate for in situ monitoring in MOVPE  

Science Journals Connector (OSTI)

Abstract Efficient photoluminescence (PL) spectra from GaN and InGaN layers at temperatures up to 1100 K are observed with low noise floor and high dynamic resolution. A number of detailed spectral features in the PL can be directly linked to physical properties of the epitaxial grown layer. The method is suggested as an in situ monitoring tool during epitaxy of nitride LED and laser structures. Layer properties like thickness, band gap or film temperature distribution are feasible.

C. Prall; M. Ruebesam; C. Weber; M. Reufer; D. Rueter

2014-01-01T23:59:59.000Z

70

Metal Nitride and Metal Carbide Nanoparticles by a Soft Urea Pathway  

Science Journals Connector (OSTI)

It also worth noting that in the presence of the metal precursors, the solubility of urea (or similar compounds) is significantly higher than in pure ethanol (4.877 g/100 g at 18.2 °C), which already indicates the formation of soluble complexes and coordination polymers. ... HRTEM shown well-developed lattice fringes, with d = 2.43 Å as interplanar distance, corresponding to the plane 101 of the hexagonal structures of gallium nitride (dcalcd = 2.43765 Å, ref ICDD-PDF4+ 01?089?7522). ... (Oxy)nitrides as new photocatalysts for water splitting under visible light irradiation ...

Cristina Giordano; Christian Erpen; Weitang Yao; Bettina Milke; Markus Antonietti

2009-10-07T23:59:59.000Z

71

Local environment and composition of magnesium gallium layered...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Local environment and composition of magnesium gallium layered double hydroxides determined from solid-state 1H and 71Ga NMR Local environment and composition of magnesium gallium...

72

Amber light-emitting diode comprising a group III-nitride nanowire active region  

DOE Patents [OSTI]

A temperature stable (color and efficiency) III-nitride based amber (585 nm) light-emitting diode is based on a novel hybrid nanowire-planar structure. The arrays of GaN nanowires enable radial InGaN/GaN quantum well LED structures with high indium content and high material quality. The high efficiency and temperature stable direct yellow and red phosphor-free emitters enable high efficiency white LEDs based on the RGYB color-mixing approach.

Wang, George T.; Li, Qiming; Wierer, Jr., Jonathan J.; Koleske, Daniel

2014-07-22T23:59:59.000Z

73

Charge transfer in Fe-doped GaN: The role of the donor  

SciTech Connect (OSTI)

Several nitride-based device structures would benefit from the availability of high quality, large-area, freestanding semi-insulating GaN substrates. Due to the intrinsic n-type nature of GaN, however, the incorporation of compensating centers such as Fe is necessary to achieve the high resistivity required. We are using electron paramagnetic resonance (EPR) to explore charge transfer in 450 um thick GaN:Fe plates to understand the basic mechanisms related to compensation so that the material may be optimized for device applications. The results suggest that the simple model based on one shallow donor and a single Fe level is insufficient to describe compensation. Rather, the observation of the neutral donor and Fe3+ indicates that either the two species are spatially segregated or additional compensating and donor defects must be present.

Sunay, Ustun; Dashdorj, J.; Zvanut, M. E.; Harrison, J. G. [Department of Physics, University of Alabama at Birmingham, 1300 University Blvd., CH 310, Birmingham, Alabama 35294-1170 (United States); Leach, J. H.; Udwary, K. [Kyma Technologies, 8829 Midway West Rd., Raleigh, North Carolina 27617 (United States)

2014-02-21T23:59:59.000Z

74

Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films  

E-Print Network [OSTI]

74 (19) 2821 (1999). F. H. Spedding, Rare-earth Elements, inby the use of rare- earth elements as color emitters inpowders activated with rare-earth elements Eu 3+ , Tb 3+ ,

Tao, Jonathan Huai-Tse

2010-01-01T23:59:59.000Z

75

Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films  

E-Print Network [OSTI]

residential lighting using incandescent lights [2], as shownenergy used for the incandescent lamp is wasted as infraredlight source to replace incandescent lighting [1]. Figure

Tao, Jonathan Huai-Tse

2010-01-01T23:59:59.000Z

76

Self- and zinc diffusion in gallium antimonide  

SciTech Connect (OSTI)

The technological age has in large part been driven by the applications of semiconductors, and most notably by silicon. Our lives have been thoroughly changed by devices using the broad range of semiconductor technology developed over the past forty years. Much of the technological development has its foundation in research carried out on the different semiconductors whose properties can be exploited to make transistors, lasers, and many other devices. While the technological focus has largely been on silicon, many other semiconductor systems have applications in industry and offer formidable academic challenges. Diffusion studies belong to the most basic studies in semiconductors, important from both an application as well as research standpoint. Diffusion processes govern the junctions formed for device applications. As the device dimensions are decreased and the dopant concentrations increased, keeping pace with Moore's Law, a deeper understanding of diffusion is necessary to establish and maintain the sharp dopant profiles engineered for optimal device performance. From an academic viewpoint, diffusion in semiconductors allows for the study of point defects. Very few techniques exist which allow for the extraction of as much information of their properties. This study focuses on diffusion in the semiconductor gallium antimonide (GaSb). As will become clear, this compound semiconductor proves to be a powerful one for investigating both self- and foreign atom diffusion. While the results have direct applications for work on GaSb devices, the results should also be taken in the broader context of III-V semiconductors. Results here can be compared and contrasted to results in systems such as GaAs and even GaN, indicating trends within this common group of semiconductors. The results also have direct importance for ternary and quaternary semiconductor systems used in devices such as high speed InP/GaAsSb/InP double heterojunction bipolar transistors (DHBT) [Dvorak, (2001)]. Many of the findings which will be reported here were previously published in three journal articles. Hartmut Bracht was the lead author on two articles on self-diffusion studies in GaSb [Bracht, (2001), (2000)], while this report's author was the lead author on Zn diffusion results [Nicols, (2001)]. Much of the information contained herein can be found in those articles, but a more detailed treatment is presented here.

Nicols, Samuel Piers

2002-03-26T23:59:59.000Z

77

Superconducting structure with layers of niobium nitride and aluminum nitride  

DOE Patents [OSTI]

A superconducting structure is formed by depositing alternate layers of aluminum nitride and niobium nitride on a substrate. Deposition methods include dc magnetron reactive sputtering, rf magnetron reactive sputtering, thin-film diffusion, chemical vapor deposition, and ion-beam deposition. Structures have been built with layers of niobium nitride and aluminum nitride having thicknesses in a range of 20 to 350 Angstroms. Best results have been achieved with films of niobium nitride deposited to a thickness of approximately 70 Angstroms and aluminum nitride deposited to a thickness of approximately 20 Angstroms. Such films of niobium nitride separated by a single layer of aluminum nitride are useful in forming Josephson junctions. Structures of 30 or more alternating layers of niobium nitride and aluminum nitride are useful when deposited on fixed substrates or flexible strips to form bulk superconductors for carrying electric current. They are also adaptable as voltage-controlled microwave energy sources.

Murduck, James M. (Lisle, IL); Lepetre, Yves J. (Lauris, FR); Schuller, Ivan K. (Woodridge, IL); Ketterson, John B. (Evanston, IL)

1989-01-01T23:59:59.000Z

78

Superconducting structure with layers of niobium nitride and aluminum nitride  

DOE Patents [OSTI]

A superconducting structure is formed by depositing alternate layers of aluminum nitride and niobium nitride on a substrate. Deposition methods include dc magnetron reactive sputtering, rf magnetron reactive sputtering, thin-film diffusion, chemical vapor deposition, and ion-beam deposition. Structures have been built with layers of niobium nitride and aluminum nitride having thicknesses in a range of 20 to 350 Angstroms. Best results have been achieved with films of niobium nitride deposited to a thickness of approximately 70 Angstroms and aluminum nitride deposited to a thickness of approximately 20 Angstroms. Such films of niobium nitride separated by a single layer of aluminum nitride are useful in forming Josephson junctions. Structures of 30 or more alternating layers of niobium nitride and aluminum nitride are useful when deposited on fixed substrates or flexible strips to form bulk superconductors for carrying electric current. They are also adaptable as voltage-controlled microwave energy sources. 8 figs.

Murduck, J.M.; Lepetre, Y.J.; Schuller, I.K.; Ketterson, J.B.

1989-07-04T23:59:59.000Z

79

Methods for improved growth of group III nitride buffer layers  

DOE Patents [OSTI]

Methods are disclosed for growing high crystal quality group III-nitride epitaxial layers with advanced multiple buffer layer techniques. In an embodiment, a method includes forming group III-nitride buffer layers that contain aluminum on suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. A hydrogen halide or halogen gas is flowing into the growth zone during deposition of buffer layers to suppress homogeneous particle formation. Some combinations of low temperature buffers that contain aluminum (e.g., AlN, AlGaN) and high temperature buffers that contain aluminum (e.g., AlN, AlGaN) may be used to improve crystal quality and morphology of subsequently grown group III-nitride epitaxial layers. The buffer may be deposited on the substrate, or on the surface of another buffer. The additional buffer layers may be added as interlayers in group III-nitride layers (e.g., GaN, AlGaN, AlN).

Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

2014-07-15T23:59:59.000Z

80

Theory and Design of Smith-Purcell Semiconductor Terahertz Sources  

E-Print Network [OSTI]

-power semiconductor devices, but have also been demonstrated to be highly useful in the development of state of the art light emitting diode (LED) technology. One of the more promising LED materials, gallium nitride (GaN) comes from the “three-nitride” (III-N) family...-power semiconductor devices, but have also been demonstrated to be highly useful in the development of state of the art light emitting diode (LED) technology. One of the more promising LED materials, gallium nitride (GaN) comes from the “three-nitride” (III-N) family...

Smith, Don DeeWayne

2013-12-06T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Nitrided Metallic Bipolar Plates  

Broader source: Energy.gov (indexed) [DOE]

to meet 5000 h automotive durability goal at cost < 5kW Year 1 Goals: Single-cell fuel cell test performance for 25 cm 2 stamped and nitrided metallic bipolar plates...

82

Boron nitride nanotubes  

DOE Patents [OSTI]

Boron nitride nanotubes are prepared by a process which includes: (a) creating a source of boron vapor; (b) mixing the boron vapor with nitrogen gas so that a mixture of boron vapor and nitrogen gas is present at a nucleation site, which is a surface, the nitrogen gas being provided at a pressure elevated above atmospheric, e.g., from greater than about 2 atmospheres up to about 250 atmospheres; and (c) harvesting boron nitride nanotubes, which are formed at the nucleation site.

Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA); Park, Cheol (Yorktown, VA)

2012-06-06T23:59:59.000Z

83

GaN High Power Devices  

SciTech Connect (OSTI)

A brief review is given of recent progress in fabrication of high voltage GaN and AlGaN rectifiers, GaN/AlGaN heterojunction bipolar transistors, GaN heterostructure and metal-oxide semiconductor field effect transistors. Improvements in epitaxial layer quality and in fabrication techniques have led to significant advances in device performance.

PEARTON,S.J.; REN,F.; ZHANG,A.P.; DANG,G.; CAO,X.A.; LEE,K.P.; CHO,H.; GILA,B.P.; JOHNSON,J.W.; MONIER,C.; ABERNATHY,C.R.; HAN,JUNG; BACA,ALBERT G.; CHYI,J.-I.; LEE,C.-M.; NEE,T.-E.; CHUO,C.-C.; CHI,G.C.; CHU,S.N.G.

2000-07-17T23:59:59.000Z

84

Cryogenic gallium phosphide acousto-optic deflectors  

Science Journals Connector (OSTI)

We present measurements of the acoustic intensity in a gallium phosphide acousto-optic deflector for the 0.6–1.3-GHz frequency range and the 8–295-K temperature range. The data show a...

Fuss, Ian; Smart, Darryn

1991-01-01T23:59:59.000Z

85

Die Bestimmung von Kupfer- und Nickelspuren in Gallium  

Science Journals Connector (OSTI)

Nickel- und Kupferkontaminierungen in Gallium im ppm-Bereich und darunter stören empfindlich bei der Verwendung in der Halbleiterphysik. Der Chloridkomplex des Galliums in 6-n HC1 wird von einem stark basische...

H. Titze

1977-01-01T23:59:59.000Z

86

GALLIUM--2000 30.1 By Deborah A. Kramer  

E-Print Network [OSTI]

the largest application for gallium, with optoelectronic devices [mostly laser diodes and light-use application for gallium, with 63% of total consumption. Optoelectronic devices accounted for 32% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

87

GALLIUM--1998 29.1 By Deborah A. Kramer  

E-Print Network [OSTI]

's) were the largest application for gallium, with optoelectronic devices [mostly laser diodes and light-use application for gallium, with 52% of total consumption. Optoelectronic devices accounted for 45% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

88

GALLIUM--1999 29.1 By Deborah A. Kramer  

E-Print Network [OSTI]

circuits (IC's) were the largest application for gallium, with optoelectronic devices [mostly laser diodes-use application for gallium, with 52% of total consumption. Optoelectronic devices accounted for 42% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

89

High-Efficiency Nitride-Based Photonic Crystal Light Sources  

Broader source: Energy.gov [DOE]

The University of California Santa Barbara (UCSB) is maximizing the efficiency of a white LED by enhancing the external quantum efficiency using photonic crystals to extract light that would normally be confined in a conventional structure. Ultimate efficiency can only be achieved by looking at the internal structure of light. To do this, UCSB is focusing on maximizing the light extraction efficiency and total light output from light engines driven by Gallium Nitride (GaN)-based LEDs. The challenge is to engineer large overlap (interaction) between modes and photonic crystals. The project is focused on achieving high extraction efficiency in LEDs, controlled directionality of emitted light, integrated design of vertical device structure, and nanoscale patterning of lateral structure.

90

Helical nanotubes of hexagonal boron nitride  

Science Journals Connector (OSTI)

......Physical: Full-length Papers Helical nanotubes of hexagonal boron nitride Masami Terauchi...Hongo, Bunkyo-ku, Tokyo 113, Japan Nanotubes of hexagonal boron nitride (h-BN...discovered. hexagonal boron nitride,|nanotube,|nanoball,|amorphous boron| C......

Masami Terauchi; Michiyoshi Tanaka; Hirofumi Matsuda; Masatoshi Takeda; Kaoru Kimura

1997-01-01T23:59:59.000Z

91

Multi-scale modelling of III-nitrides: from dislocations to the electronic structure  

E-Print Network [OSTI]

or public lighting nowadays use GaN-based LEDs. Significant effort is being invested in development of efficient and reliable LEDs which emit comfort- able white light, as there is a huge market potential for replacing bulbs and fluorescent tubes currently... of wurtzite forms of the III-nitrides. The range of the visible spectrum is shown on the wavelength axis. GaN and its alloys with aluminium or indium are in their stable form, wurtzite direct band gap semicon- ductors that have become the most important since...

Holec, David

92

Superplastic forging nitride ceramics  

DOE Patents [OSTI]

The invention relates to producing relatively flaw free silicon nitride ceramic shapes requiring little or no machining by superplastic forging This invention herein was made in part under Department of Energy Grant DE-AC01-84ER80167, creating certain rights in the United States Government. The invention was also made in part under New York State Science and Technology Grant SB1R 1985-10.

Panda, Prakash C. (Ithaca, NY); Seydel, Edgar R. (Ithaca, NY); Raj, Rishi (Ithaca, NY)

1988-03-22T23:59:59.000Z

93

Method for Plutonium-Gallium Separation by Anodic Dissolution of a Solid Plutonium-Gallium Alloy  

SciTech Connect (OSTI)

Purified plutonium and gallium are efficiently recovered from a solid plutonium-gallium (Pu-Ga) alloy by using an electrorefining process. The solid Pu-Ga alloy is the cell anode, preferably placed in a moving basket within the electrolyte. As the surface of the Pu-Ga anode is depleted in plutonium by the electrotransport of the plutonium to a cathode, the temperature of the electrolyte is sufficient to liquify the surface, preferably at about 500 C, resulting in a liquid anode layer substantially comprised of gallium. The gallium drips from the liquified surface and is collected below the anode within the electrochemical cell. The transported plutonium is collected on the cathode surface and is recovered.

Miller, William E.; Tomczuk, Zygmunt

1998-12-08T23:59:59.000Z

94

Metalorganic chemical vapor deposition of GaN on Si(111): Stress control and application to field-effect transistors  

SciTech Connect (OSTI)

Two schemes of nucleation and growth of gallium nitride on Si(111) substrates are investigated and the structural and electrical properties of the resulting films are reported. Gallium nitride films grown using a 10{endash}500 nm-thick AlN buffer layer deposited at high temperature ({similar_to}1050{degree}C) are found to be under 260{endash}530 MPa of tensile stress and exhibit cracking, the origin of which is discussed. The threading dislocation density in these films increases with increasing AlN thickness, covering a range of 1.1 to {gt}5.8{times}10{sup 9}cm{sup {minus}2}. Films grown using a thick, AlN-to-GaN graded buffer layer are found to be under compressive stress and are completely crack free. Heterojunction field effect transistors fabricated on such films result in well-defined saturation and pinch-off behavior with a saturated current of {similar_to}525 mA/mm and a transconductance of {similar_to}100 mS/mm in dc operation. {copyright} 2001 American Institute of Physics.

Marchand, H.; Zhao, L.; Zhang, N.; Moran, B.; Coffie, R.; Mishra, U. K.; Speck, J. S.; DenBaars, S. P.; Freitas, J. A.

2001-06-15T23:59:59.000Z

95

Functionalized boron nitride nanotubes  

DOE Patents [OSTI]

A plasma treatment has been used to modify the surface of BNNTs. In one example, the surface of the BNNT has been modified using ammonia plasma to include amine functional groups. Amine functionalization allows BNNTs to be soluble in chloroform, which had not been possible previously. Further functionalization of amine-functionalized BNNTs with thiol-terminated organic molecules has also been demonstrated. Gold nanoparticles have been self-assembled at the surface of both amine- and thiol-functionalized boron nitride Nanotubes (BNNTs) in solution. This approach constitutes a basis for the preparation of highly functionalized BNNTs and for their utilization as nanoscale templates for assembly and integration with other nanoscale materials.

Sainsbury, Toby; Ikuno, Takashi; Zettl, Alexander K

2014-04-22T23:59:59.000Z

96

Interactions of zircaloy cladding with gallium -- 1997 status  

SciTech Connect (OSTI)

A four phase program has been implemented to evaluate the effect of gallium in mixed oxide (MOX) fuel derived from weapons grade (WG) plutonium on Zircaloy cladding performance. The objective is to demonstrate that low levels of gallium will not compromise the performance of the MOX fuel system in LWR. This graded, four phase experimental program will evaluate the performance of prototypic Zircaloy cladding materials against: (1) liquid gallium (Phase 1), (2) various concentrations of Ga{sub 2}O{sub 3} (Phase 2), (3) centrally heated surrogate fuel pellets with expected levels of gallium (Phase 3), and (4) centrally heated prototypic MOX fuel pellets (Phase 4). This status report describes the results of an initial series of tests for phases 1 and 2. Three types of tests are being performed: (1) corrosion, (2) liquid metal embrittlement (LME), and (3) corrosion mechanical. These tests are designed to determine the corrosion mechanisms, thresholds for temperature and concentration of gallium that may delineate behavioral regimes, and changes in mechanical properties of Zircaloy. Initial results have generally been favorable for the use of WG-MOX fuel. The MOX fuel cladding, Zircaloy, does react with gallium to form intermetallic compounds at {ge} 300 C; however, this reaction is limited by the mass of gallium and is therefore not expected to be significant with a low level (in parts per million) of gallium in the MOX fuel. While continued migration of gallium into the initially formed intermetallic compound results in large stresses that can lead to distortion, this is also highly unlikely because of the low mass of gallium or gallium oxide present and expected clad temperatures below 400 C. Furthermore, no evidence for grain boundary penetration by gallium has been observed.

Wilson, D.F.; DiStefano, J.R.; King, J.F.; Manneschmidt, E.T.; Strizak, J.P.

1997-11-01T23:59:59.000Z

97

Interactions of Zircaloy cladding with gallium: 1998 midyear status  

SciTech Connect (OSTI)

A program has been implemented to evaluate the effect of gallium in mixed-oxide (MOX) fuel derived from weapons-grade (WG) plutonium on Zircaloy cladding performance. The objective is to demonstrate that low levels of gallium will not compromise the performance of the MOX fuel system in a light-water reactor. The graded, four-phase experimental program was designed to evaluate the performance of prototypic Zircaloy cladding materials against (1) liquid gallium (Phase 1), (2) various concentrations of Ga{sub 2}O{sub 3} (Phase 2), (3) centrally heated surrogate fuel pellets with expected levels of gallium (Phase 3), and (4) centrally heated prototypic MOX fuel pellets (Phase 4). This status report describes the results of a series of tests for Phases 1 and 2. Three types of tests are being performed: (1) corrosion, (2) liquid metal embrittlement, and (3) corrosion-mechanical. These tests will determine corrosion mechanisms, thresholds for temperature and concentration of gallium that may delineate behavioral regimes, and changes in the mechanical properties of Zircaloy. Initial results have generally been favorable for the use of WG-MOX fuel. The MOX fuel cladding, Zircaloy, does react with gallium to form intermetallic compounds at {ge}300 C; however, this reaction is limited by the mass of gallium and is therefore not expected to be significant with a low level (parts per million) of gallium in the MOX fuel. Although continued migration of gallium into the initially formed intermetallic compound can result in large stresses that may lead to distortion, this was shown to be extremely unlikely because of the low mass of gallium or gallium oxide present and expected clad temperatures below 400 C. Furthermore, no evidence for grain boundary penetration by gallium has been observed.

Wilson, D.F.; DiStefano, J.R.; Strizak, J.P.; King, J.F.; Manneschmidt, E.T.

1998-06-01T23:59:59.000Z

98

Cordierite silicon nitride filters  

SciTech Connect (OSTI)

The objective of this project was to develop a silicon nitride based crossflow filter. This report summarizes the findings and results of the project. The project was phased with Phase I consisting of filter material development and crossflow filter design. Phase II involved filter manufacturing, filter testing under simulated conditions and reporting the results. In Phase I, Cordierite Silicon Nitride (CSN) was developed and tested for permeability and strength. Target values for each of these parameters were established early in the program. The values were met by the material development effort in Phase I. The crossflow filter design effort proceeded by developing a macroscopic design based on required surface area and estimated stresses. Then the thermal and pressure stresses were estimated using finite element analysis. In Phase II of this program, the filter manufacturing technique was developed, and the manufactured filters were tested. The technique developed involved press-bonding extruded tiles to form a filter, producing a monolithic filter after sintering. Filters manufactured using this technique were tested at Acurex and at the Westinghouse Science and Technology Center. The filters did not delaminate during testing and operated and high collection efficiency and good cleanability. Further development in areas of sintering and filter design is recommended.

Sawyer, J.; Buchan, B. (Acurex Environmental Corp., Mountain View, CA (United States)); Duiven, R.; Berger, M. (Aerotherm Corp., Mountain View, CA (United States)); Cleveland, J.; Ferri, J. (GTE Products Corp., Towanda, PA (United States))

1992-02-01T23:59:59.000Z

99

High intensity x-ray source using liquid gallium target  

DOE Patents [OSTI]

A high intensity x-ray source that uses a flowing stream of liquid gallium as a target with the electron beam impinging directly on the liquid metal.

Smither, Robert K. (Hinsdale, IL); Knapp, Gordon S. (Cupertino, CA); Westbrook, Edwin M. (Chicago, IL); Forster, George A. (Westmont, IL)

1990-01-01T23:59:59.000Z

100

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

(nanowires) in the compound gallium selenide. In short, ordered lines of structural vacancies in the material stimulate the growth of "one-dimensional" structures less than 1...

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Nitrides Race Beyond the Light  

Science Journals Connector (OSTI)

...are far from the limit,” Palacios says. Nitride transistors might also prove essential for a variety of future “smart grid” applications. First, however, they must be able to withstand transmitting large amounts of power, something silicon-based...

Robert F. Service

2010-03-26T23:59:59.000Z

102

Superplastic forging nitride ceramics  

DOE Patents [OSTI]

A process is disclosed for preparing silicon nitride ceramic parts which are relatively flaw free and which need little or no machining, said process comprising the steps of: (a) preparing a starting powder by wet or dry mixing ingredients comprising by weight from about 70% to about 99% silicon nitride, from about 1% to about 30% of liquid phase forming additive and from 1% to about 7% free silicon; (b) cold pressing to obtain a preform of green density ranging from about 30% to about 75% of theoretical density; (c) sintering at atmospheric pressure in a nitrogen atmosphere at a temperature ranging from about 1,400 C to about 2,200 C to obtain a density which ranges from about 50% to about 100% of theoretical density and which is higher than said preform green density, and (d) press forging workpiece resulting from step (c) by isothermally uniaxially pressing said workpiece in an open die without initial contact between said workpiece and die wall perpendicular to the direction of pressing and so that pressed workpiece does not contact die wall perpendicular to the direction of pressing, to substantially final shape in a nitrogen atmosphere utilizing a temperature within the range of from about 1,400 C to essentially 1,750 C and strain rate within the range of about 10[sup [minus]7] to about 10[sup [minus]1] seconds[sup [minus]1], the temperature and strain rate being such that surface cracks do not occur, said pressing being carried out to obtain a shear deformation greater than 30% whereby superplastic forging is effected.

Panda, P.C.; Seydel, E.R.; Raj, R.

1988-03-22T23:59:59.000Z

103

Effect of strain on low-loss electron energy loss spectra of group-III nitrides  

Science Journals Connector (OSTI)

Thin films of AlN experiencing different strain states were investigated with a scanning transmission electron microscope (STEM) by low-loss electron energy loss spectroscopy (EELS). The results conclude that the low-loss properties and in particular, the plasmon peak position is shifted as a direct consequence of the inherent strain of the sample. The results reveal that strain, even minor levels, can be measured by STEM-EELS. These results were further corroborated by full potential calculations and expanded to include the similar III nitrides GaN and InN. It is found that a unit-cell volume change of 1% results in a bulk plasmon peak shift of 0.159, 0.168, and 0.079 eV for AlN, GaN, and InN, respectively, according to simulations. The AlN peak shift was experimentally corroborated with a corresponding peak shift of 0.156 eV. The unit-cell volume is used here since it is found that regardless of in- and out-of-plane lattice augmentation, the low-loss properties appear near identical for constant volume. These results have an impact on the interpretation of the plasmon energy and its applicability for determining and separating stress and composition. It is found that while the bulk plasmon energy can be used as a measure of the composition in a group-III nitride alloy for relaxed structures, the presence of strain significantly affects such a measurement. The strain is found to have a lower impact on the peak shift for Al1-xInxN (?3% compositional error per 1% volume change) and In1-xGaxN alloys compared to significant variations for Al1-xGaxN (16% compositional error for 1% volume change). Hence a key understanding in low-loss studies of III nitrides is that strain and composition are coupled and affect one another.

J. Palisaitis; C.-L. Hsiao; M. Junaid; J. Birch; L. Hultman; P. O. Å. Persson

2011-12-07T23:59:59.000Z

104

Inhibition of Protein Tyrosine Phosphatase by the Antitumor Agent Gallium Nitrate  

Science Journals Connector (OSTI)

...Gallium is known to bind to the iron transport protein transferrin...NSC 166828. gallium, tris(acetylacetonate). The gallium nitrate:transferrin...the binding of gallium to the iron transport protein transferrin...and incorporation into the iron storage protein ferritin...

Margareta M. Berggren; Leigh Ann Burns; Robert T. Abraham; and Garth Powis

1993-04-15T23:59:59.000Z

105

Boron Nitride Porous Microbelts for Hydrogen Storage  

Science Journals Connector (OSTI)

Boron Nitride Porous Microbelts for Hydrogen Storage ... However, the attention paid to their potential applications in gas sorption, especially in case of hydrogen, has obviously been insufficient. ... boron nitride; porous; microbelts; specific surface area; hydrogen storage ...

Qunhong Weng; Xuebin Wang; Chunyi Zhi; Yoshio Bando; Dmitri Golberg

2013-01-09T23:59:59.000Z

106

Growth Kinetics and Doping of Gallium Nitride Grown by rf-Plasma Assisted Molecular Beam Epitaxy  

E-Print Network [OSTI]

Thomas H. Myers, Ph.D., Chair Larry E. Halliburton, Ph.D. Nancy C. Giles, Ph.D. Charter D. Stinespring Giles, Dr. Charter Stinespring, Dr. Larry Halliburton, and Dr. Mohindar Seehra. In addition, I would

Myers, Tom

107

Unusual strategies for using indium gallium nitride grown on silicon (111) for solid-state lighting  

Science Journals Connector (OSTI)

...lighting research and development: Multi-year program plan) ( US DoE , Washington, DC ) Available from http://www1.eere.energy.gov/buildings/ssl/techroadmaps.html . 6 Karlicek RF Jr ( 2005 ) Conference on Lasers and Electro-optics...

Hoon-sik Kim; Eric Brueckner; Jizhou Song; Yuhang Li; Seok Kim; Chaofeng Lu; Joshua Sulkin; Kent Choquette; Yonggang Huang; Ralph G. Nuzzo; John A. Rogers

2011-01-01T23:59:59.000Z

108

Unusual strategies for using indium gallium nitride grown on silicon (111) for solid-state lighting  

Science Journals Connector (OSTI)

...of Materials Science and Engineering...Mechanical and Aerospace Engineering...energy. Further advances in this technology...that extend our recent work in flexible electronics...of Materials Sciences under Award...funded by National Science Foundation...energy. Further advances in this technology...

Hoon-sik Kim; Eric Brueckner; Jizhou Song; Yuhang Li; Seok Kim; Chaofeng Lu; Joshua Sulkin; Kent Choquette; Yonggang Huang; Ralph G. Nuzzo; John A. Rogers

2011-01-01T23:59:59.000Z

109

Professor Mathias Schubert explains his study of indium gallium nitride semiconductor systems, which  

E-Print Network [OSTI]

generation of multiple-junction solar energy conversion devices with improved ease of manufacture, cost within a sample. Conversely, the blue light-emitting diodes (LEDs) intended for transferring from energy free charge carrier properties in contact- based electrical measurements, in the extreme case

Farritor, Shane

110

Temperature dependence of plasmonic terahertz absorption in grating-gate gallium-nitride transistor structures  

Science Journals Connector (OSTI)

Strong plasmon resonances have been observed in the terahertz transmission spectra (1–5 THz) of large-area slit-grating-gate AlGaN/GaN-based high-electron-mobility transistor(HEMT) structures at temperatures from 10 to 170 K. The resonance frequencies correspond to the excitation of plasmons with wave vectors equal to the reciprocal lattice vectors of the metal grating which serves both as a gate electrode for the HEMT and a coupler between plasmons and incident terahertz radiation. Wide tunability of the resonances by the applied gate voltage demonstrates potential of these devices for terahertz applications.

A. V. Muravjov; D. B. Veksler; V. V. Popov; O. V. Polischuk; N. Pala; X. Hu; R. Gaska; H. Saxena; R. E. Peale; M. S. Shur

2010-01-01T23:59:59.000Z

111

Process for making transition metal nitride whiskers  

DOE Patents [OSTI]

A process for making metal nitrides, particularly titanium nitride whiskers, using a cyanide salt as a reducing agent for a metal compound in the presence of an alkali metal oxide. Sodium cyanide, various titanates and titanium oxide mixed with sodium oxide react to provide titanium nitride whiskers that can be used as reinforcement to ceramic composites. 1 fig., 1 tab.

Bamberger, C.E.

1988-04-12T23:59:59.000Z

112

P-type doping of GaN  

SciTech Connect (OSTI)

After implantation of As, As + Be, and As + Ga into GaN and annealing for short durations at temperatures as high as 1500 C, the GaN films remained highly resistive. It was apparent from c-RBS studies that although implantation damage did not create an amorphous layer in the GaN film, annealing at 1500 C did not provide enough energy to completely recover the radiation damage. Disorder recovered significantly after annealing at temperatures up to 1500 C, but not completely. From SIMS analysis, oxygen contamination in the AIN capping layer causes oxygen diffusion into the GaN film above 1400 C. The sapphire substrate (A1203) also decomposed and oxygen penetrated into the backside of the GaN layer above 1400 C. To prevent donor-like oxygen impurities from the capping layer and the substrate from contaminating the GaN film and compensating acceptors, post-implantation annealing should be done at temperatures below 1500 C. Oxygen in the cap could be reduced by growing the AIN cap on the GaN layer after the GaN growth run or by depositing the AIN layer in a ultra high vacuum (UHV) system post-growth to minimize residual oxygen and water contamination. With longer annealing times at 1400 C or at higher temperatures with a higher quality AIN, the implantation drainage may fully recover.

Wong, R.K.

2000-04-10T23:59:59.000Z

113

Development of a Bulk GaN Growth Technique for Low Defect Density, Large-Area Native Substrates  

Broader source: Energy.gov (indexed) [DOE]

Next-Generation Power Electronics: Next-Generation Power Electronics: Electrochemical Solution Growth (ESG) Technique for Bulk Gallium Nitride Substrates Karen Waldrip Dept. 2546, Advanced Power Sources R&D Sandia National Labs, Albuquerque, NM knwaldr@sandia.gov, (505) 844-1619 Acknowledgements: Mike Soboroff, Stan Atcitty, Nancy Clark, and John Boyes David Ingersoll, Frank Delnick, and Travis Anderson 2010 DOE Peer Review, Nov. 2-4, Washington, DC Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Funded by the Energy Storage Systems Program of the U.S. Department Of Energy through Sandia National Laboratories Project Objective

114

Compatibility of ITER candidate structural materials with static gallium  

SciTech Connect (OSTI)

Tests were conducted on the compatibility of gallium with candidate structural materials for the International Thermonuclear Experimental Reactor, e.g., Type 316 SS, Inconel 625, and Nb-5 Mo-1 Zr alloy, as well as Armco iron, Nickel 270, and pure chromium. Type 316 stainless steel is least resistant to corrosion in static gallium and Nb-5 Mo-1 Zr alloy is most resistant. At 400{degrees}C, corrosion rates are {approx}4.0, 0.5, and 0.03 mm/yr for type 316 SS, Inconel 625, and Nb-5 Mo- 1 Zr alloy, respectively. The pure metals react rapidly with gallium. In contrast to findings in earlier studies, pure iron shows greater corrosion than nickel. The corrosion rates at 400{degrees}C are {ge}88 and 18 mm/yr, respectively, for Armco iron and Nickel 270. The results indicate that at temperatures up to 400{degrees}C, corrosion occurs primarily by dissolution and is accompanied by formation of metal/gallium intermetallic compounds. The solubility data for pure metals and oxygen in gallium are reviewed. The physical, chemical, and radioactive properties of gallium are also presented. The supply and availability of gallium, as well as price predictions through the year 2020, are summarized.

Luebbers, P.R.; Michaud, W.F.; Chopra, O.K.

1993-12-01T23:59:59.000Z

115

Behavior of Zircaloy Cladding in the Presence of Gallium  

SciTech Connect (OSTI)

The U.S. Department of Energy has established a dual-track approach to the disposition of plutonium arising from the dismantling of nuclear weapons. Both immobilization and reactor-based mixed-oxide (MOX) fuel technologies are being evaluated. The reactor-based MOX fuel option requires assessment of the potential impact of concentrations of gallium (on the order of 1 to 10 ppm), not present in conventional MOX fuel, on cladding material performance. An experimental program was designed to evaluate the performance of prototypic Zircaloy cladding materials against (1) liquid gallium, and (2) various concentrations of G~03. Three types of tests were performed: (1) corrosion, (2) liquid metal embrittlement, and (3) corrosion-mechanical. These tests were to determine corrosion mechanisms, thresholds for temperature and concentration of gallium that delineate behavioral regimes, and changes in the mechanical properties of Zircaloy. Results have generally been favorable for the use of weapons-grade (WG) MOX fhel. The Zircaloy cladding does react with gallium to form intermetallic compounds at >3000 C; however, this reaction is limited by the mass of gallium and is therefore not expected to be significant with a low level (parts per million) of gallium in the MOX fuel. Furthermore, no evidence for grain boundary penetration by gallium or liquid metal embrittlement was observed.

DiStefano, J.R.; King, J.F.; Manneschmidt, E.T.; Strizak, J.P.; Wilson, D.F.

1998-09-28T23:59:59.000Z

116

Development of an Infrastructure for the Growth and Characterization of GaN on Nitrided Sapphire  

E-Print Network [OSTI]

and prospered. To Dr. C. Stinespring and his lab members I would like to thank for the use of the facilities and specifically Jeff Gold for the mass spectrometer measurements. I would also like to thank Dr. C. Stinespring

Myers, Tom

117

(Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary (crude, unrefined) gallium was recovered in 2013. Globally,  

E-Print Network [OSTI]

% of the gallium consumed was used in integrated circuits (ICs). Optoelectronic devices, which include laser diodes of the remaining gallium consumption. Optoelectronic devices were used in aerospace applications, consumer goods

118

Large area supersonic jet epitaxy of AlN, GaN, and SiC on silicon  

SciTech Connect (OSTI)

AlN, GaN, and SiC thin films were grown on 100 mm diameter Si(111) and Si(100) substrates using Supersonic Jet Epitaxy (SJE). Precursor gases were seeded in lighter mass carrier gases and free jets were formed using novel slit-jet apertures. The jet design, combined with substrate rotation, allowed for a uniform flux distribution over a large area of a 100 mm wafer at growth pressures of 1--20 mTorr. Triethylaluminum, triethylgallium, and ammonia were used for nitride growth, while disilane, acetylene, and methylsilane were used for SiC growth. The films were characterized by in situ optical reflectivity, x-ray diffraction (XRD), atomic force microscopy (AFM), and spectroscopic ellipsometry (SE).

Lauhon, L.J.; Ustin, S.A.; Ho, W. [Cornell Univ., Ithaca, NY (United States). Dept. of Physics

1997-12-31T23:59:59.000Z

119

Role of gallium-67 in the clinical evaluation of cancer  

SciTech Connect (OSTI)

This review is based primarily on historic data, and it examines the indications for and limitations of gallium-67 scanning in the evaluation of patients with neoplasms. The use of gallium-67 scans is discussed according to tumor type, and data from the most representative and comprehensive studies are included. The results described, some of which were obtained primarily with older imaging techniques, should be regarded as representing the minimum that can be expected from application of this imaging procedure.

Bekerman, C.; Hoffer, P.B.; Bitran, J.D.

1984-10-01T23:59:59.000Z

120

Self-aligned submicron gate length gallium arsenide MESFET  

E-Print Network [OSTI]

SELF-ALIGNED SUBMICRON GATE LENGTH GALLIUM ARSENIDE MESFET A Thesis by HSIEN-CHING HUANG Submitted to the Graduate College of Texas ASSAM University in partial fulfillment of the requirement for the degree ol' MASTER OF SCIENCE May 1987... Major Subject: Electrical Engineering SELF-ALIGNED SUBMICRON GATE LENGTH GALLIUM ARSENIDE MESFET A Thesis by HSIEN-CHING HUANG Approved as to style and content by: Mark. H. Weichold (Chairman of Committee) Donald L. Parker (Member) dali L...

Huang, Hsien-Ching

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

It's Elemental - Isotopes of the Element Gallium  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Zinc Zinc Previous Element (Zinc) The Periodic Table of Elements Next Element (Germanium) Germanium Isotopes of the Element Gallium [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 69 60.108% STABLE 71 39.892% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 56 No Data Available Proton Emission (suspected) No Data Available 57 No Data Available Proton Emission (suspected) No Data Available 58 No Data Available Proton Emission (suspected) No Data Available 59 No Data Available Proton Emission (suspected) No Data Available 60 70 milliseconds Electron Capture 98.40%

122

Cavity optomechanics in gallium phosphide microdisks  

SciTech Connect (OSTI)

We demonstrate gallium phosphide (GaP) microdisk optical cavities with intrinsic quality factors >2.8?×?10{sup 5} and mode volumes <10(?/n){sup 3}, and study their nonlinear and optomechanical properties. For optical intensities up to 8.0?×?10{sup 4} intracavity photons, we observe optical loss in the microcavity to decrease with increasing intensity, indicating that saturable absorption sites are present in the GaP material, and that two-photon absorption is not significant. We observe optomechanical coupling between optical modes of the microdisk around 1.5??m and several mechanical resonances, and measure an optical spring effect consistent with a theoretically predicted optomechanical coupling rate g{sub 0}/2??30?kHz for the fundamental mechanical radial breathing mode at 488?MHz.

Mitchell, Matthew; Barclay, Paul E., E-mail: pbarclay@ucalgary.ca [Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); National Institute for Nanotechnology, 11421 Saskatchewan Dr. NW, Edmonton, Alberta T6G 2M9 (Canada); Hryciw, Aaron C. [National Institute for Nanotechnology, 11421 Saskatchewan Dr. NW, Edmonton, Alberta T6G 2M9 (Canada)

2014-04-07T23:59:59.000Z

123

CX-010973: Categorical Exclusion Determination  

Broader source: Energy.gov [DOE]

Advanced Low-Cost Silicon Carbide (SiC) and Gallium Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction... CX(s) Applied: B3.6 Date: 09/16/2013 Location(s): Arkansas Offices(s): National Energy Technology Laboratory

124

CX-011468: Categorical Exclusion Determination  

Broader source: Energy.gov [DOE]

Advanced Low-Cost Silicon-Carbide (SiC) and Gallium-Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction... CX(s) Applied: B3.6 Date: 10/29/2013 Location(s): Michigan Offices(s): National Energy Technology Laboratory

125

CX-010974: Categorical Exclusion Determination  

Broader source: Energy.gov [DOE]

Advanced Low-Cost Silicon Carbide (SiC) and Gallium Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction... CX(s) Applied: B3.6 Date: 09/16/2013 Location(s): Arkansas Offices(s): National Energy Technology Laboratory

126

Hybrid structure laser based on semiconductor nanowires and a silica microfiber knot cavity  

E-Print Network [OSTI]

.1063/1.3093821 Semiconductor lasers based on cadmium sulfide CdS , zinc oxide ZnO , gallium nitride GaN nanowires, and gal-earth doped microfiber knot laser with knot diameter below 1 mm failed due to the insufficient pump absorption

Wu, Shin-Tson

127

Characterization and Modeling of Silicon Carbide Power Devices and Paralleling Operation  

E-Print Network [OSTI]

Characterization and Modeling of Silicon Carbide Power Devices and Paralleling Operation Yutian Cui silicon carbide (SiC) power devices. The devices have been tested for both static and dynamic like silicon carbide (SiC) and gallium nitride (GaN) are becoming more attractive. SiC power devices

Tolbert, Leon M.

128

Nitrided Metallic Bipolar Plates | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Nitrided Metallic Bipolar Plates Mass Production Cost Estimation for Direct H2 PEM Fuel Cell Systems for Automotive Applications: 2010 Update Mass Production Cost Estimation...

129

Nanostructure, Chemistry and Crystallography of Iron Nitride...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Nanostructure, Chemistry and Crystallography of Iron Nitride Magnetic Materials by Ultra-High-Resolution Electron Microscopy and Related Methods Nanostructure, Chemistry and...

130

Process for forming pure silver ohmic contacts to N- and P-type gallium arsenide materials  

DOE Patents [OSTI]

Disclosed is an improved process for manufacturing gallium arsenide semiconductor devices having as its components a n-type gallium arsenide substrate layer and a p-type gallium arsenide diffused layer. The improved process comprises forming a pure silver ohmic contact to both the diffuse layer and the substrate layer wherein the n-type layer comprises a substantially low doping carrier concentration.

Hogan, S.J.

1983-03-13T23:59:59.000Z

131

Gallium based low-interaction anions  

DOE Patents [OSTI]

The present invention provides: a composition of the formula M.sup.+x (Ga(Y).sub.4.sup.-).sub.x where M is a metal selected from the group consisting of lithium, sodium, potassium, cesium, calcium, strontium, thallium, and silver, x is an integer selected from the group consisting of 1 or 2, each Y is a ligand selected from the group consisting of aryl, alkyl, hydride and halide with the proviso that at least one Y is a ligand selected from the group consisting of aryl, alkyl and halide; a composition of the formula (R).sub.x Q.sup.+ Ga(Y).sub.4.sup.- where Q is selected from the group consisting of carbon, nitrogen, sulfur, phosphorus and oxygen, each R is a ligand selected from the group consisting of alkyl, aryl, and hydrogen, x is an integer selected from the group consisting of 3 and 4 depending upon Q, and each Y is a ligand selected from the group consisting of aryl, alkyl, hydride and halide with the proviso that at least one Y is a ligand selected from the group consisting of aryl, alkyl and halide; an ionic polymerization catalyst composition including an active cationic portion and a gallium based weakly coordinating anion; and bridged anion species of the formula M.sup.+x.sub.y [X(Ga(Y.sub.3).sub.z ].sup.-y.sub.x where M is a metal selected from the group consisting of lithium, sodium, potassium, magnesium, cesium, calcium, strontium, thallium, and silver, x is an integer selected from the group consisting of 1 or 2, X is a bridging group between two gallium atoms, y is an integer selected from the group consisting 1 and 2, z is an integer of at least 2, each Y is a ligand selected from the group consisting of aryl, alkyl, hydride and halide with the proviso that at least one Y is a ligand selected from the group consisting of aryl, alkyl and halide.

King, Wayne A. (Santa Fe, NM); Kubas, Gregory J. (Santa Fe, NM)

2000-01-01T23:59:59.000Z

132

Bamboo-like boron nitride nanotubes  

Science Journals Connector (OSTI)

......Full-length paper Bamboo-like boron nitride nanotubes Renzhi Ma Yoshio Bando Tadao Sato To...305-0044, Japan Bamboo-like boron nitride nanotubes (BN-NTs), synthesized from melamine...the temperature gradient applied in the nanotube growth process was considered as the......

Renzhi Ma; Yoshio Bando; Tadao Sato

2002-03-01T23:59:59.000Z

133

Atomic-Level Study of Melting Behavior of GaN Nanotubes. | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Melting Behavior of GaN Nanotubes. Atomic-Level Study of Melting Behavior of GaN Nanotubes. Abstract: Molecular dynamics simulations with a Stillinger-Weber potential have been...

134

E-Print Network 3.0 - aln gan inn Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: size. Introduction GaN and its alloys with InN and AlN have been used for optoelectronic devices... region. The formation of self-assembled GaN nanostructures on aluminum...

135

Molten-Salt-Based Growth of Group III Nitrides  

DOE Patents [OSTI]

A method for growing Group III nitride materials using a molten halide salt as a solvent to solubilize the Group-III ions and nitride ions that react to form the Group III nitride material. The concentration of at least one of the nitride ion or Group III cation is determined by electrochemical generation of the ions.

Waldrip, Karen E. (Albuquerque, NM); Tsao, Jeffrey Y. (Albuquerque, NM); Kerley, Thomas M. (Albuquerque, NM)

2008-10-14T23:59:59.000Z

136

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Vacancy-Induced Nanoscale Wire Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Wednesday, 21 December 2005 00:00 Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the University of Washington has demonstrated a new way of creating one-dimensional nanoscale structures (nanowires) in the compound gallium selenide. In short, ordered lines of structural vacancies in the material stimulate the growth of "one-dimensional" structures less than 1 nanometer in width.

137

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the University of Washington has demonstrated a new way of creating one-dimensional nanoscale structures (nanowires) in the compound gallium selenide. In short, ordered lines of structural vacancies in the material stimulate the growth of "one-dimensional" structures less than 1 nanometer in width.

138

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the University of Washington has demonstrated a new way of creating one-dimensional nanoscale structures (nanowires) in the compound gallium selenide. In short, ordered lines of structural vacancies in the material stimulate the growth of "one-dimensional" structures less than 1 nanometer in width.

139

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the University of Washington has demonstrated a new way of creating one-dimensional nanoscale structures (nanowires) in the compound gallium selenide. In short, ordered lines of structural vacancies in the material stimulate the growth of "one-dimensional" structures less than 1 nanometer in width.

140

K.K. Gan EPS 2001 1 New Results on Charm  

E-Print Network [OSTI]

K.K. Gan EPS 2001 1 New Results on Charm Semileptonic Decays and Lifetime K.K. Gan The Ohio State University July 14, 2001 Representing CLEO Collaboration #12;K.K. Gan EPS 2001 2 l measurement of l first+ B(D+ K* 0 l+ l ) (D*+ ) c + #12;K.K. Gan EPS 2001 3 l P measurement of form factors helps to guide

Gan, K. K.

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

E-Print Network 3.0 - amorphous silicon nitride Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

nitride, aluminium oxide, titanium nitride are promising materials for the high... of powder analysis made by the following processes: - Preparation of silicon nitride by...

142

Aluminum Nitride Micro-Channels Grown via Metal Organic Vapor Phase Epitaxy for MEMs Applications  

SciTech Connect (OSTI)

Aluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nanoelectromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro-channels for fuel cell applications, and micromechanical resonators. This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ģm to 110 ģm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.

Rodak, L.E.; Kuchibhatla, S.; Famouri, P.; Ting, L.; Korakakis, D.

2008-01-01T23:59:59.000Z

143

Synthesis of transition metal nitride by nitridation of metastable oxide precursor  

SciTech Connect (OSTI)

Metastable transition metal oxides were used as precursors to synthesize transition metal nitrides at low temperature. Amorphous MoO{sub 2} was prepared by reduction of (NH{sub 4}){sub 6}Mo{sub 7}O{sub 24} solution with hydrazine. As-synthesized amorphous MoO{sub 2} was transformed into fcc {gamma}-Mo{sub 2}N at 400 Degree-Sign C and then into hexagonal {delta}-MoN by further increasing the temperature to 600 Degree-Sign C under a NH{sub 3} flow. The nitridation temperature employed here is much lower than that employed in nitridation of crystalline materials, and the amorphous materials underwent a unique nitridation process. Besides this, the bimetallic nitride Ni{sub 2}Mo{sub 3}N was also synthesized by nitridating amorphous bimetallic precursor. These results suggested that the nitridation of amorphous precursor possessed potential to be a general method for synthesizing many interstitial metallic compounds, such as nitrides and carbides at low temperature. - graphical abstract: Amorphous oxide was used as new precursor to prepare nitride at low temperature. Pure {gamma}-Mo{sub 2}N and {delta}-MoN were obtained at 400 Degree-Sign C and at 600 Degree-Sign C, respectively. Highlights: Black-Right-Pointing-Pointer We bring out a new method to synthesize transition metal nitrides at low temperature. Black-Right-Pointing-Pointer Both mono- and bimetallic molybdenum nitrides were synthesized at a mild condition. Black-Right-Pointing-Pointer The formation of two different molybdenum nitrides {gamma}-Mo{sub 2}N and {delta}-MoN can be controlled from the same metastable precursor. Black-Right-Pointing-Pointer The nitridation temperature was much lower than that reported from crystalline precursors. Black-Right-Pointing-Pointer The metastable precursor had different reaction process in comparison with crystalline precursor.

Wang, Huamin; Wu, Zijie; Kong, Jing [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China)] [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China); Wang, Zhiqiang, E-mail: zqwang@mail.nankai.edu.cn [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China) [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China); Tianjin Key Laboratory of Water Environment and Resources, Tianjin Normal University, No. 393 Binshui Road, Xiqing Dist., Tianjin 300387 (China); Zhang, Minghui, E-mail: zhangmh@nankai.edu.cn [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China)] [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China)

2012-10-15T23:59:59.000Z

144

Joint ATLAS/CMS SLHC Opto WG 1 K.K. Gan Lesson Learned from  

E-Print Network [OSTI]

Joint ATLAS/CMS SLHC Opto WG 1 K.K. Gan Lesson Learned from ATLAS Pixel Optical Link #12;Joint ATLAS/CMS SLHC Opto WG 2 Outline Introduction VCSEL/PIN monitoring Analysis of opto-board/VCSEL/PIN failures Summary K.K. Gan #12;K.K. Gan Joint ATLAS/CMS SLHC Opto WG 3 Introduction Architecture

Gan, K. K.

145

K.K. Gan ATLAS Tracker Upgrade Workshop 1 Progress Report on Joint ATLAS/CMS  

E-Print Network [OSTI]

K.K. Gan ATLAS Tracker Upgrade Workshop 1 Progress Report on Joint ATLAS/CMS SLHC Opto ATLAS Tracker Upgrade Workshop 2 Outline Introduction Subgroups activities Summary #12;K.K. Gan ATLAS System #12;K.K. Gan ATLAS Tracker Upgrade Workshop 4 Group A: Lesson Learned and to be Learned from LHC

Gan, K. K.

146

Maskless lateral epitaxial overgrowth of GaN on sapphire  

SciTech Connect (OSTI)

The authors demonstrate a technique of lateral epitaxial overgrowth (LEO) of GaN, termed maskless LEO, in which no mask is deposited prior to LEO regrowth. Instead, a bulk (> 2 {micro}m) GaN layer on sapphire is selectively dry etched, leaving {approximately} 5 {micro}m-wide stripe mesas oriented in the <10{bar 1}0>{sub GaN} direction, with a 20 {micro}m period. These stripes serve as seeds for LEO GaN growth, which proceeds from the tops of the stripes and expands laterally, resulting in a T, or overhang, morphology. As for LEO over an SiO{sub 2} mask, significant defect reduction (from {approximately} 10{sup 9} cm{sup {minus}2} to {approximately} 10{sup 6} cm{sup {minus}2}) is observed in cross-sectional transmission electron microscopy (TEM). Atomic force microscopy of the top surface of the LEO GaN reveals that no threading dislocations with screw component terminate at the surfaces of laterally overgrown regions. X-ray diffraction measurements reveal that the wings exhibit a crystallographic tilt away from the seed regions in an azimuth perpendicular to the stripe direction; the tilt angle ({approximately} 0.4--0.5{degree}) is relatively independent of growth temperature and wing aspect ratio.

Fini, P.; Marchand, H.; Ibbetson, J.P.; Moran, B.; Zhao, L.; Denbaars, S.P.; Speck, J.S.; Mishra, U.K.

1999-07-01T23:59:59.000Z

147

GALLIUM--1997 29.1 By Deborah A. Kramer  

E-Print Network [OSTI]

As is manufactured into optoelectronic devices (LED's, laser diodes, photodetectors, and solar cells) and integrated consumption. Optoelectronic devices accounted for 44% of domestic consumption, and the remaining 7% was used by imports, primarily high-purity gallium from France and low-purity material from Russia. Optoelectronic

148

Sputtering of tin and gallium-tin clusters  

SciTech Connect (OSTI)

Tin and gallium-tin clusters have been produced by 4 keV Ar{sup +} ion bombardment of polycrystalline tin and the gallium-tin eutectic alloy and analyzed by time-of-flight mass spectrometry. The sputtered neutral species were photoionized with 193 nm (6.4 eV) excimer laser light. Neutral tin clusters containing up to 10 atoms and mixed gallium-tin clusters Ga{sub (n-m)}Sn{sub m} with n {<=} 4 for the neutrals and N {<=} 3 for the sputtered ionic species have been detected. Laser power density dependent intensity measurements, relative yields, and kinetic energy distributions have been measured. The abundance distributions of the mixed clusters have been found to be nonstatistical due to significant differences in the ionization efficiencies for clusters with equal nuclearity but different number of tin atoms. The results indicate that Ga{sub 2}Sn and Ga{sub 3}Sn like the all-gallium clusters have ionization potentials below 6.4 eV. In the case of Sn{sub 5}, Sn{sub 6}, GaSn and Ga{sub (n-m)}Sn{sub m} clusters with n=2 to 4 and m>1, the authors detect species that have sufficient internal energy to be one photon ionized despite ionization potentials that are higher 6.4 eV. The tin atom signal that is detected can be attributed to photofragmentation of dimers for both sputtering from polycrystalline tin and from the gallium-tin eutectic alloy.

Lill, T.; Calaway, W.F.; Ma, Z.; Pellin, M.J.

1994-08-01T23:59:59.000Z

149

Method of nitriding refractory metal articles  

DOE Patents [OSTI]

A method of nitriding a refractory-nitride forming metal or metalloid articles and composite articles. A consolidated metal or metalloid article or composite is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article or composite is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article or composite is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid or composite to an article or composite of refractory nitride. In addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

Tiegs, Terry N. (Lenoir City, TN); Holcombe, Cressie E. (Knoxville, TN); Dykes, Norman L. (Oak Ridge, TN); Omatete, Ogbemi O. (Lagos, NG); Young, Albert C. (Flushing, NY)

1994-01-01T23:59:59.000Z

150

Method of nitriding refractory metal articles  

DOE Patents [OSTI]

A method of nitriding a refractory-nitride forming metal or metalloid articles and composite articles. A consolidated metal or metalloid article or composite is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article or composite is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article or composite is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid or composite to an article or composite of refractory nitride. In addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

Tiegs, T.N.; Holcombe, C.E.; Dykes, N.L.; Omatete, O.O.; Young, A.C.

1994-03-15T23:59:59.000Z

151

Silicon nitride having a high tensile strength  

DOE Patents [OSTI]

A ceramic body is disclosed comprising at least about 80 w/o silicon nitride and having a mean tensile strength of at least about 800 MPa. 4 figs.

Pujari, V.K.; Tracey, D.M.; Foley, M.R.; Paille, N.I.; Pelletier, P.J.; Sales, L.C.; Willkens, C.A.; Yeckley, R.L.

1998-06-02T23:59:59.000Z

152

Low temperature route to uranium nitride  

DOE Patents [OSTI]

A method of preparing an actinide nitride fuel for nuclear reactors is provided. The method comprises the steps of a) providing at least one actinide oxide and optionally zirconium oxide; b) mixing the oxide with a source of hydrogen fluoride for a period of time and at a temperature sufficient to convert the oxide to a fluoride salt; c) heating the fluoride salt to remove water; d) heating the fluoride salt in a nitrogen atmosphere for a period of time and at a temperature sufficient to convert the fluorides to nitrides; and e) heating the nitrides under vacuum and/or inert atmosphere for a period of time sufficient to convert the nitrides to mononitrides.

Burrell, Anthony K. (Los Alamos, NM); Sattelberger, Alfred P. (Darien, IL); Yeamans, Charles (Berkeley, CA); Hartmann, Thomas (Idaho Falls, ID); Silva, G. W. Chinthaka (Las Vegas, NV); Cerefice, Gary (Henderson, NV); Czerwinski, Kenneth R. (Henderson, NV)

2009-09-01T23:59:59.000Z

153

Catalytic hydrodesulfurization by molybdenum nitride  

SciTech Connect (OSTI)

High surface area molybdenum nitride (up to 108 m{sup 2}/g) was synthesized, characterized, and tested for thiophene desulfurization activity. The surface area was found to depend on synthesis temperature profile, mass transfer, and passivation procedure. Passivated and sulfided catalysts retained the bulk structure of face-centered-cubic Mo{sub 2}N. X-ray diffraction and Raman spectroscopy showed no evidence for MoO{sub 3} or MoS{sub 2} formation in fresh catalysts or catalysts sulfided at 673 K. Thiophene desulfurization activity was measured over a broad range Mo{sub 2}N surface areas and reactor condition. Small amounts of tetrahydrothiophene were formed during desulfurization and low-conversion data at 673 K indicate that butane is one of the initial products of the thiophene desulfurization reaction, in addition to butadiene and the butenes.

Markel, E.J.; Van Zee, J.W. (Univ. of South Carolina, Columbia (USA))

1990-12-01T23:59:59.000Z

154

The Nitrogen-Nitride Anode.  

SciTech Connect (OSTI)

Nitrogen gas N 2 can be reduced to nitride N -3 in molten LiCl-KCl eutectic salt electrolyte. However, the direct oxidation of N -3 back to N 2 is kinetically slow and only occurs at high overvoltage. The overvoltage for N -3 oxidation can be eliminated by coordinating the N -3 with BN to form the dinitridoborate (BN 2 -3 ) anion which forms a 1-D conjugated linear inorganic polymer with -Li-N-B-N- repeating units. This polymer precipitates out of solution as Li 3 BN 2 which becomes a metallic conductor upon delithiation. Li 3 BN 2 is oxidized to Li + + N 2 + BN at about the N 2 /N -3 redox potential with very little overvoltage. In this report we evaluate the N 2 /N -3 redox couple as a battery anode for energy storage.

Delnick, Frank M.

2014-10-01T23:59:59.000Z

155

Corrosion behavior of mesoporous transition metal nitrides  

SciTech Connect (OSTI)

Transition metal nitrides (TMN) have many desirable characteristics such as high hardness and good thermal stability under reducing conditions. This work reports an initial survey of the chemical stability of mesoporous TMNs (TM=Nb, V, Cr and Ti) in water at 80 °C at neutral, acidic and alkaline pH. The mesoporous TMNs had specific surface areas of 25–60 m{sup 2}/g with average pore sizes ranging from 10 to 50 nm. The high surface areas of these materials enhance the rate of corrosion per unit mass over that of a bulk material, making detection of corrosion much easier. The products were characterized by Rietveld refinement of powder X-ray diffraction (PXRD) patterns and by scanning electron microscopy (SEM). Several nitrides have corrosion rates that are, within error, not distinguishable from zero (±1 Å/day). Of the nitrides examined, CrN appears to be the most corrosion resistant under acidic conditions. None of the nitrides studied are corrosion resistant under alkaline conditions. - Graphical abstract: Corrosion behavior of mesoporous transition metal nitrides (TM=Nb, V, Cr and Ti) in acidic and alkaline solutions at 80 °C for 2 weeks. Display Omitted - highlights: • Corrosion rates of mesoporous transition metal nitrides in aqueous solution is reported. • The mesoporous TMNs had surface areas of 25–60 m{sup 2}/g. • CrN is the most corrosion resistant under the conditions studied.

Yang, Minghui, E-mail: m.yang@cornell.edu [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States); Allen, Amy J.; Nguyen, Minh T. [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States); Ralston, Walter T. [College of Chemistry, University of California, Berkeley 94720-1460, CA (United States); MacLeod, Michelle J. [Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139-4307, MA (United States); DiSalvo, Francis J., E-mail: fjd3@cornell.edu [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States)

2013-09-15T23:59:59.000Z

156

E-Print Network 3.0 - arsenide- gallium instrument Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: of gallium arsenide, a semiconductor, which is used in advanced optoelectronics, lasers, microwave circuits... , and solar cells. To determine material...

157

Boron-Nitride Nanotubes Show Potential in Cancer Treatment |...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Boron-Nitride Nanotubes Show Potential in Cancer Treatment NEWPORT NEWS, VA, April 26 - A new study has shown that adding boron-nitride nanotubes to the surface of cancer cells can...

158

Preparation Of Copper Indium Gallium Diselenide Films For Solar Cells  

DOE Patents [OSTI]

High quality thin films of copper-indium-gallium-diselenide useful in the production of solar cells are prepared by electrodepositing at least one of the constituent metals onto a glass/Mo substrate, followed by physical vapor deposition of copper and selenium or indium and selenium to adjust the final stoichiometry of the thin film to approximately Cu(In,Ga)Se.sub.2. Using an AC voltage of 1-100 KHz in combination with a DC voltage for electrodeposition improves the morphology and growth rate of the deposited thin film. An electrodeposition solution comprising at least in part an organic solvent may be used in conjunction with an increased cathodic potential to increase the gallium content of the electrodeposited thin film.

Bhattacharya, Raghu N. (Littleton, CO); Contreras, Miguel A. (Golden, CO); Keane, James (Lakewood, CO); Tennant, Andrew L. (Denver, CO), Tuttle, John R. (Denver, CO); Ramanathan, Kannan (Lakewood, CO); Noufi, Rommel (Golden, CO)

1998-08-08T23:59:59.000Z

159

The Russian-American Gallium solar neutrino Experiment  

SciTech Connect (OSTI)

The Russian-American Gallium solar neutrino Experiment (SAGE) is described. The solar neutrino flux measured by 31 extractions through October, 1993 is presented. The result of 69 {+-} 10{sub {minus}7}{sup +5} SNU is to be compared with a standard solar model prediction of 132 SNU. The status of a {sup 51}Cr neutrino source irradiation to test the overall operation of the experiment is also presented.

Elliott, S.R. [Univ. of Washington, Seattle, WA (United States); Abdurashitov, J.N. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. for Nuclear Research; Bowles, T.J. [Los Alamos National Lab., NM (United States)] [and others

1995-12-31T23:59:59.000Z

160

The Russian-American gallium solar neutrino experiment  

SciTech Connect (OSTI)

The Russian-American Gallium solar neutrino Experiment (SAGE) is described. The solar neutrino flux measured by 31 extractions through October, 1993 is presented. The result of 69 {+-} 10{sub {minus}7}{sup +5} SNU is to be compared with a standard solar model prediction of 132 SNU. The status of a {sup 51}Cr neutrino source irradiation to test the overall operation of the experiment is also presented.

Elliott, S.R.; Wilkerson, J.F. [Univ. of Washington, Seattle, WA (United States); Abdurashitov, J.N. [Russian Academy of Sciences, Moscow (Russian Federation). Institute of Nuclear Research] [and others

1995-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Si in GaN -- On the nature of the background donor  

SciTech Connect (OSTI)

A characterization of the Si impurity in GaN is performed by Raman spectroscopy. Applying hydrostatic pressure up to 25 GPa the authors study the behavior of the LO phonon-plasmon mode in a series of high mobility Si doped GaN films. In contrast to earlier results on unintentionally doped bulk GaN crystals no freeze out of the free carriers could be observed in Si doped samples. The authors find that Si is a shallow hydrogenic donor throughout the pressure range studied. This result positively excludes Si incorporation as a dominant source of free electrons in previously studied bulk GaN samples.

Wetzel, C.; Chen, A.L.; Suski, T.; Ager, J.W. III; Walukiewicz, W. [Lawrence Berkeley National Lab., CA (United States). Materials Science Div.

1996-08-01T23:59:59.000Z

162

Structural defects in GaN revealed by Transmission Electron Microscopy  

SciTech Connect (OSTI)

This paper reviews the various types of structural defects observed by Transmission Electron Microscopy in GaN heteroepitaxial layers grown on foreign substrates and homoepitaxial layers grown on bulk GaN substrates. The structural perfection of these layers is compared to the platelet self-standing crystals grown by High Nitrogen Pressure Solution. Defects in undoped and Mg doped GaN are discussed. Some models explaining the formation of inversion domains in heavily Mg doped layers that are possible defects responsible for the difficulties of p-doping in GaN are also reviewed.

Liliental-Weber, Zuzanna

2014-04-18T23:59:59.000Z

163

Evaluation of silicon-nitride ceramic valves.  

SciTech Connect (OSTI)

Silicon-nitride ceramic valves can improve the performance of both light- and heavy-duty automotive engines because of the superior material properties of silicon nitrides over current metal alloys. However, ceramics are brittle materials that may introduce uncertainties in the reliability and durability of ceramic valves. As a result, the lifetime of ceramic valves are difficult to predict theoretically due to wide variations in the type and distribution of microstructural flaws in the material. Nondestructive evaluation (NDE) methods are therefore required to assess the quality and reliability of these valves. Because ceramic materials are optically translucent and the strength-limiting flaws are normally located near the valve surface, a laser-scatter method can be used for NDE evaluation of ceramic valves. This paper reviews the progress in the development of this NDE method and its application to inspect silicon-nitride ceramic valves at various stages of manufacturing and bench and engine tests.

Sun, J. G.; Zhang, J. M.; Andrews, M. J.; Tretheway, J. S.; Phillips, N. S .L.; Jensen, J. A.; Nuclear Engineering Division; Univ. of Texas; Caterpillar, Inc.

2008-01-01T23:59:59.000Z

164

GALLIUM NITRIDE INTEGRATED GAS/TEMPERATURE SENSORS FOR FUEL CELL SYSTEM MONITORING FOR HYDROGEN AND CARBON MONOXIDE  

E-Print Network [OSTI]

on field effect devices using catalytic metal gates on silicon carbide substrates has been reviewed (Spetz-10%) of transition metals such as copper, silver, and chromium (Feinstein et al 1997 and Pyke 1993). High temperature. Introduction Gas sensing and analysis based on gas adsorption on a catalytic metal surface has been extensively

165

The influence of framework-gallium in zeolites: Electronegativity and infrared spectroscopic study  

SciTech Connect (OSTI)

Based on the influence of the composition (Si/Al and Si/Ga ratio) on the framework vibrations of zeolites with different structure types (FAU, LTL, BETA, MOR, MEL, MFI, TON, and MTW), an electronegativity value for gallium substituted into zeolite frameworks is proposed (Sanderson electronegativity scale). The present electronegativity value agrees with the known physicochemical properties of gallium substituted zeolites.

Dompas, D.H.; Mortier, W.J. (Katholieke Univ. Leuven (Belgium)); Kenter, O.C.H. (Delft Univ. of Technology (The Netherlands)); Janssen, M.J.G.; Verduijn, J.P. (Exxon Chemical Holland, Rotterdam (The Netherlands))

1991-05-01T23:59:59.000Z

166

Two-photon photovoltaic effect in gallium arsenide Jeff Chiles,1  

E-Print Network [OSTI]

Two-photon photovoltaic effect in gallium arsenide Jichi Ma,1 Jeff Chiles,1 Yagya D. Sharma,2 214669); published September 4, 2014 The two-photon photovoltaic effect is demonstrated in gallium; (230.0250) Optoelectronics; (040.5350) Photovoltaic; (130.4310) Nonlinear. http://dx.doi.org/10.1364/OL

Fathpour, Sasan

167

IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 2, APRIL 2012 123 Gallium Arsenide Solar Cell Absorption  

E-Print Network [OSTI]

IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 2, APRIL 2012 123 Gallium Arsenide Solar Cell Absorption flat gallium arsenide solar cell, we show that it is possible to modify the flow of light and enhance above the solar cell. The incoupling element is lossless and, thus, has the advantage that no energy

Grandidier, Jonathan

168

Diffusion of indium and gallium in Cu(In,Ga)Se2 thin film solar cells  

E-Print Network [OSTI]

Diffusion of indium and gallium in Cu(In,Ga)Se2 thin film solar cells O. Lundberga,*, J. Lua , A. Rockettb , M. Edoffa , L. Stolta a AĀ°ngstroĀØm Solar Center, Uppsala University, P.O. Box 534, SE-751 21 Abstract The diffusion of indium and gallium in polycrystalline thin film Cu(In,Ga)Se2 layers has been

Rockett, Angus

169

Gallium/aluminum nanocomposite material for nonlinear optics and nonlinear plasmonics  

E-Print Network [OSTI]

Gallium/aluminum nanocomposite material for nonlinear optics and nonlinear plasmonics A. V penetration of gallium into an aluminum film. These composite films form mirrorlike interfaces with silica optics and active plasmonics. The material is a polycrystalline aluminum film on a silica sub- strate

Zheludev, Nikolay

170

Synthesis and use of (polyfluoroaryl)fluoroanions of aluminum, gallium and indium  

DOE Patents [OSTI]

Salts of (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are described. The (polyfluoroaryl)fluoroanions have the formula [ER'R"R'"F].sup..crclbar. wherein E is aluminum, gallium, or indium, wherein F is fluorine, and wherein R', R", and R'" is each a fluorinated phenyl, fluorinated biphenyl, or fluorinated polycyclic group.

Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

2000-01-01T23:59:59.000Z

171

Dynamic Model of Hydrogen in GaN  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Dynamic Model of Hydrogen in GaN by S. M. Myers and A. F. Wright Motivation-Hydrogen is incorporated into p-type GaN during MOCVD growth, producing highly stable passivation of the Mg acceptors. Complete acceptor activation by thermal H release requires temperatures that threaten material integrity, prompting compromises in device processing. At lower temperatures, forward bias of p-n junctions or electron-beam irradiation produces a metastable, reversible activation without H release. To understand and control such effects, we are developing a mathematical model of H behavior wherein state energies from density-functional theory are employed in diffusion-reaction equations. Previously, we used the greatly simplifying assumptions of local equilibrium among states

172

Anisotropic Hexagonal Boron Nitride Nanomaterials - Synthesis and Applications  

SciTech Connect (OSTI)

Boron nitride (BN) is a synthetic binary compound located between III and V group elements in the Periodic Table. However, its properties, in terms of polymorphism and mechanical characteristics, are rather close to those of carbon compared with other III-V compounds, such as gallium nitride. BN crystallizes into a layered or a tetrahedrally linked structure, like those of graphite and diamond, respectively, depending on the conditions of its preparation, especially the pressure applied. Such correspondence between BN and carbon readily can be understood from their isoelectronic structures [1, 2]. On the other hand, in contrast to graphite, layered BN is transparent and is an insulator. This material has attracted great interest because, similar to carbon, it exists in various polymorphic forms exhibiting very different properties; however, these forms do not correspond strictly to those of carbon. Crystallographically, BN is classified into four polymorphic forms: Hexagonal BN (h-BN) (Figure 1(b)); rhombohedral BN (r-BN); cubic BN (c-BN); and wurtzite BN (w-BN). BN does not occur in nature. In 1842, Balmain [3] obtained BN as a reaction product between molten boric oxide and potassium cyanide under atmospheric pressure. Thereafter, many methods for its synthesis were reported. h-BN and r-BN are formed under ambient pressure. c-BN is synthesized from h-BN under high pressure at high temperature while w-BN is prepared from h-BN under high pressure at room temperature [1]. Each BN layer consists of stacks of hexagonal plate-like units of boron and nitrogen atoms linked by SP{sup 2} hybridized orbits and held together mainly by Van der Waals force (Fig 1(b)). The hexagonal polymorph has two-layered repeating units: AA'AA'... that differ from those in graphite: ABAB... (Figure 1(a)). Within the layers of h-BN there is coincidence between the same phases of the hexagons, although the boron atoms and nitrogen atoms are alternatively located along the c-axis. The rhombohedral system consists of three-layered units: ABCABC..., whose honeycomb layers are arranged in a shifted phase, like as those of graphite. Reflecting its weak interlayer bond, the h-BN can be cleaved easily along its layers, and hence, is widely used as a lubricant material. The material is stable up to a high temperature of 2300 C before decomposition sets in [2] does not fuse a nitrogen atmosphere of 1 atm, and thus, is applicable as a refractory material. Besides having such properties, similar to those of graphite, the material is transparent, and acts as a good electric insulator, especially at high temperatures (10{sup 6} {Omega}m at 1000 C) [1]. c-BN and w-BN are tetrahedrally linked BN. The former has a cubic sphalerite-type structure, and the latter has a hexagonal wurtzite-type structure. c-BN is the second hardest known material (the hardest is diamond), the so-called white diamond. It is used mainly for grinding and cutting industrial ferrous materials because it does not react with molten iron, nickel, and related alloys at high temperatures whereas diamond does [1]. It displays the second highest thermal conductivity (6-9 W/cm.deg) after diamond. This chapter focuses principally upon information about h-BN nanomaterials, mainly BN nanotubes (BNNTs), porous BN, mono- and few-layer-BN sheets. There are good reviews book chapters about c-BN in [1, 4-6].

Han,W.Q.

2008-08-01T23:59:59.000Z

173

Titanium nitride electrodes for thermoelectric generators  

DOE Patents [OSTI]

The invention is directed to a composite article suitable for use in thermoelectric generators. The article comprises a thin film of titanium nitride as an electrode deposited onto solid electrolyte. The invention is also directed to the method of making same.

Novak, Robert F. (Farmington Hills, MI); Schmatz, Duane J. (Dearborn Heights, MI); Hunt, Thomas K. (Ann Arbor, MI)

1987-12-22T23:59:59.000Z

174

K.K. Gan Siena02 1 The Ohio State University  

E-Print Network [OSTI]

.K. Gan Siena02 6 l Decode Bi-Phase Mark encoded (BPM) clock and command signals from PIN diode l Input Error Rate (BER): BPM #12;K.K. Gan Siena02 7 l Training period: ~25 ms of 20 MHz clock (BPM with no data) DORIC Logic ] Ready

Gan, K. K.

175

Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy  

E-Print Network [OSTI]

Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy A. J. Ptak, L. J-assisted molecular-beam epitaxy to study the dependence of oxygen incorporation on polarity and oxygen partial pressure. Oxygen incorporates at a rate ten times faster on nitrogen-polar GaN than on the Ga polarity

Myers, Tom

176

Categorical Exclusion Determinations: Arkansas | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Arkansas Arkansas Categorical Exclusion Determinations: Arkansas Location Categorical Exclusion Determinations issued for actions in Arkansas. DOCUMENTS AVAILABLE FOR DOWNLOAD September 16, 2013 CX-010974: Categorical Exclusion Determination Advanced Low-Cost Silicon Carbide (SiC) and Gallium Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction... CX(s) Applied: B3.6 Date: 09/16/2013 Location(s): Arkansas Offices(s): National Energy Technology Laboratory September 16, 2013 CX-010973: Categorical Exclusion Determination Advanced Low-Cost Silicon Carbide (SiC) and Gallium Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction... CX(s) Applied: B3.6 Date: 09/16/2013 Location(s): Arkansas Offices(s): National Energy Technology Laboratory

177

Microsoft PowerPoint - Gallium Oxide_Ramana  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Gallium Oxide Nanostructures Gallium Oxide Nanostructures for High Temperature Sensors C.V. Ramana (PI) Evgeny Shafirovich (Co-PI) Mechanical Engineering, University of Texas at El Paso Students: Ernesto Rubio (PhD); S.K. Samala (MS) A.K. Narayana Swamy (PhD); K. Abhilash (MS) Program Manager: Richard Dunst, NETL, DOE Project: DE-FE0007225 Project Period: 10/01/2011 to 09/31/2014 1 06/12/2013 DOE UCR/HBCU Conference, June 11-13, 2013 2 ļ‚· Introduction ļ‚· Research Objectives ļ‚· Experiments ā–ŗ Synthesis ā–ŗ Characterization ļ‚· Results and Discussion ā–ŗ Pure Ga 2 O 3 Thin Films ā–ŗ W-doped Ga 2 O 3 Thin Films (Physical Methods) ļ‚· Summary & Future Work 06/12/2013 DOE UCR/HBCU Conference, June 11-13, 2013 3 06/12/2013 DOE UCR/HBCU Conference, June 11-13, 2013 4 Energy Systems High-T High-T High-P High-P

178

E-Print Network 3.0 - aligned carbon nitride Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

nitride-coated electroless nickelaluminum masters. The sub- strate material... replica removal through differential contraction in liquid nitrogen. Carbon nitride is a...

179

E-Print Network 3.0 - americium nitrides Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

carbides and nitrides for the inert matrix fuel by spark plasma sintering Summary: in carbide or nitride matrix to fabricate oxide-dispersed IMF pellets. Further study using...

180

Tunnel-injection quantum dot deep-ultraviolet light-emitting diodes with polarization-induced doping in III-nitride heterostructures  

SciTech Connect (OSTI)

Efficient semiconductor optical emitters in the deep-ultraviolet spectral window are encountering some of the most deep rooted problems of semiconductor physics. In III-Nitride heterostructures, obtaining short-wavelength photon emission requires the use of wide bandgap high Al composition AlGaN active regions. High conductivity electron (n-) and hole (p-) injection layers of even higher bandgaps are necessary for electrical carrier injection. This approach requires the activation of very deep dopants in very wide bandgap semiconductors, which is a difficult task. In this work, an approach is proposed and experimentally demonstrated to counter the challenges. The active region of the heterostructure light emitting diode uses ultrasmall epitaxially grown GaN quantum dots. Remarkably, the optical emission energy from GaN is pushed from 365?nm (3.4?eV, the bulk bandgap) to below 240?nm (>5.2?eV) because of extreme quantum confinement in the dots. This is possible because of the peculiar bandstructure and band alignments in the GaN/AlN system. This active region design crucially enables two further innovations for efficient carrier injection: Tunnel injection of carriers and polarization-induced p-type doping. The combination of these three advances results in major boosts in electroluminescence in deep-ultraviolet light emitting diodes and lays the groundwork for electrically pumped short-wavelength lasers.

Verma, Jai, E-mail: jverma@nd.edu; Islam, S. M.; Protasenko, Vladimir; Kumar Kandaswamy, Prem; Xing, Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

2014-01-13T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

16 - Applications of Refractory Carbides and Nitrides  

Science Journals Connector (OSTI)

Publisher Summary This chapter reviews the applications of refractory carbides and nitrides in each of the following industrial categories: (1) automotive and aerospace, (2) industrial machinery and equipment, (3) cutting and grinding tools, (4) armor, (5) nuclear, (6) semiconductor, and (6) optical. Many of the automotive and aerospace applications of refractory carbides and nitrides are of a structural and chemical nature, especially in applications involving high temperature and/or corrosive environments where most metals are no longer suitable. These applications are usually in the bulk form and are made possible by recent advances in processing technology. Relatively large parts can now be produced to near-net shape with little machining required. Applications of refractory carbides and nitrides are found extensively in machinery and equipment for protection against wear, erosion, and chemical attack. Both bulk materials and coatings are used. The most important bulk material is tungsten carbide sintered with a metallic binder that is usually cobalt. Cutting and grinding tools are a special case of wear and corrosion applications. Cutting tools have a sharp edge for the purpose of shaving and generating a material chip. This edge must remain sharp for the tool to perform properly. Grinding tools are different in that they have an abrasive-coated surface that generates a powder as opposed to the chip of a cutting tool.

Hugh O. Pierson

1996-01-01T23:59:59.000Z

182

All-optical Wavelength Conversion in Aluminum Gallium Arsenide at Telecommunications Wavelengths.  

E-Print Network [OSTI]

??This thesis aims at both developing highly nonlinear Aluminum Gallium Arsenide waveguides(AlGaAs) and demonstrating all-optical wavelength conversion via cross-phase modulation in AlGaAs waveguides at telecommunications… (more)

Ng, Wing-Chau

2011-01-01T23:59:59.000Z

183

E-Print Network 3.0 - aluminum gallium indium Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

4F84E-A98D-4D11-B923-779B4467077F Unexpected Discovery Could Yield Full Spectrum Solar Cell Summary: elements from group III of the periodic table, like aluminum, gallium, and...

184

GALLIUM--2002 29.1 References that include a section mark () are found in the Internet  

E-Print Network [OSTI]

consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic devices application for gallium, with 46% of total consumption. Optoelectronic devices accounted for 42% of domestic

185

Polycrystalline Thin-Film Research: Copper Indium Gallium Diselenide (Fact Sheet)  

SciTech Connect (OSTI)

Capabilities fact sheet for the National Center for Photovoltaics: Polycrystalline Thin-Film Research: Copper Indium Gallium Diselenide that includes scope, core competencies and capabilities, and contact/web information.

Not Available

2011-06-01T23:59:59.000Z

186

Fabrication of optoelectronic microwave linear and ring resonators on a gallium arsenide substrate  

E-Print Network [OSTI]

FABRICATION OF OPTOELECTRONIC MICROWAVE LINEAR AND RING RESONATORS ON A GALLIUM ARSENIDE SUBSTRATE A Thesis by CHUN-LIANG YEH Submitted to the Office of Graduate Studies of Texas ASM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1993 Major Subject: Electrical Engineering FABRICATION OF OPTOELECTRONIC MICROWAVE LINEAR AND RING RESONATORS ON A GALLIUM ARSENIDE SUBSTRATE A Thesis by CHUN-LIANG YEH Approved as to style and content by: Mark...

Yeh, Chun-Liang

1993-01-01T23:59:59.000Z

187

Optical resonance modes in GaN pyramid microcavities  

SciTech Connect (OSTI)

An array of GaN hexagonal pyramids with a side length of 8.0 {mu}m was fabricated by selective epitaxial overgrowth. These microsized pyramids are highly efficient microcavities. Three types of optical resonance modes with mode spacings of 10, 5.0, and 6.0 {Angstrom} were observed when a single pyramid was pumped optically by an intense ultraviolet laser beam. An optical ray tracing method has been developed for calculating the optical resonance modes inside the pyramid microcavities. It was shown that a single pyramidal cavity can support several different types of optical resonance modes. The calculated mode spacing agrees very well with the observations. The uniqueness and advantages of this class of hexagonal pyramidal microcavities over the other microcavities are discussed. The implications of our finding on the future GaN microcavity light emitters including micro-light-emitting diodes, microcavity lasers, and vertical-cavity-surface emitting lasers are also discussed. {copyright} {ital 1999 American Institute of Physics.}

Jiang, H.X.; Lin, J.Y.; Zeng, K.C. [Department of Physics, Kansas State University, Manhattan, Kansas 66506-2601 (United States)] [Department of Physics, Kansas State University, Manhattan, Kansas 66506-2601 (United States); Yang, W. [Honeywell Technology Center, Plymouth, Minnesota 55441 (United States)] [Honeywell Technology Center, Plymouth, Minnesota 55441 (United States)

1999-08-01T23:59:59.000Z

188

Study of Magnetohydrodynamic Surface Waves on Liquid Gallium  

SciTech Connect (OSTI)

Magnetohydrodynamic (MHD) surface waves on liquid gallium are studied theoretically and experimentally in the small magnetic Reynolds number limit. A linear dispersion relation is derived when a horizontal magnetic field and a horizontal electric current is imposed. No wave damping is found in the shallow liquid limit while waves always damp in the deep liquid limit with a magnetic field parallel to the propagation direction. When the magnetic field is weak, waves are weakly damped and the real part of the dispersion is unaffected, while in the opposite limit waves are strongly damped with shortened wavelengths. In a table-top experiment, planar MHD surface waves on liquid gallium are studied in detail in the regime of weak magnetic field and deep liquid. A non-invasive diagnostic accurately measures surface waves at multiple locations by reflecting an array of lasers off the surface onto a screen, which is recorded by an Intensified-CCD camera. The measured dispersion relation is consistent with the linear theory with a reduced surface tension likely due to surface oxidation. In excellent agreement with linear theory, it is observed that surface waves are damped only when a horizontal magnetic field is imposed parallel to the propagation direction. No damping is observed under a perpendicular magnetic field. The existence of strong wave damping even without magnetic field suggests the importance of the surface oxide layer. Implications to the liquid metal wall concept in fusion reactors, especially on the wave damping and a Rayleigh-Taylor instability when the Lorentz force is used to support liquid metal layer against gravity, are discussed.

Hantao Ji; William Fox; David Pace; H.L. Rappaport

2004-05-13T23:59:59.000Z

189

Process for producing ceramic nitrides anc carbonitrides and their precursors  

DOE Patents [OSTI]

A process for preparing ceramic nitrides and carbon nitrides in the form of very pure, fine particulate powder. Appropriate precursors is prepared by reaching a transition metal alkylamide with ammonia to produce a mixture of metal amide and metal imide in the form of an easily pyrolyzable precipitate.

Brown, G.M.; Maya, L.

1987-02-25T23:59:59.000Z

190

Process for making boron nitride using sodium cyanide and boron  

DOE Patents [OSTI]

This a very simple process for making boron nitride by mixing sodium cyanide and boron phosphate and heating the mixture in an inert atmosphere until a reaction takes place. The product is a white powder of boron nitride that can be used in applications that require compounds that are stable at high temperatures and that exhibit high electrical resistance.

Bamberger, Carlos E. (Oak Ridge, TN)

1990-01-01T23:59:59.000Z

191

Oxidation Protection of Uranium Nitride Fuel using Liquid Phase Sintering  

SciTech Connect (OSTI)

Two methods are proposed to increase the oxidation resistance of uranium nitride (UN) nuclear fuel. These paths are: (1) Addition of USi{sub x} (e.g. U3Si2) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with various compounds (followed by densification via Spark Plasma Sintering or Liquid Phase Sintering) that will greatly increase oxidation resistance. The advantages (high thermal conductivity, very high melting point, and high density) of nitride fuel have long been recognized. The sodium cooled BR-10 reactor in Russia operated for 18 years on uranium nitride fuel (UN was used as the driver fuel for two core loads). However, the potential advantages (large power up-grade, increased cycle lengths, possible high burn-ups) as a Light Water Reactor (LWR) fuel are offset by uranium nitride's extremely low oxidation resistance (UN powders oxidize in air and UN pellets decompose in hot water). Innovative research is proposed to solve this problem and thereby provide an accident tolerant LWR fuel that would resist water leaks and high temperature steam oxidation/spalling during an accident. It is proposed that we investigate two methods to increase the oxidation resistance of UN: (1) Addition of USi{sub x} (e.g. U{sub 3}Si{sub 2}) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with compounds (followed by densification via Spark Plasma Sintering) that will greatly increase oxidation resistance.

Dr. Paul A. Lessing

2012-03-01T23:59:59.000Z

192

Atomic Layer Deposition of Insulating Hafnium and Zirconium Nitrides  

E-Print Network [OSTI]

author. E-mail: gordon@chemistry.harvard.edu. (1) Toth, L. E. Transition Metal Carbides and Nitrides homoleptic tetrakis(dialkylamido)- metal(IV) complexes and ammonia at low substrate temperatures (150-250 Ā°C). The precursor vapors were alternately pulsed into a heated reactor, yielding 1.15-1.20 Ć? of metal nitride film

193

Watching GaN Nanowires Grow Eric A. Stach,*, Peter J. Pauzauskie, Tevye Kuykendall,  

E-Print Network [OSTI]

Vision, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Uni and experimentally demonstrated that congruent sublimation of GaN is possible, which yields diatomic or polymeric

Yang, Peidong

194

In situ studies of the effect of silicon on GaN growth modes.  

SciTech Connect (OSTI)

We present real-time X-ray scattering studies of the influence of silicon on the homoepitaxial growth mode of GaN grown by metal-organic vapor-phase epitaxy. Both annealing of Si-doped GaN and surface dosing of GaN with disilane are shown to change the mode of subsequent growth from step-flow to layer-by-layer. By comparing the growth behavior induced by doped layers which have been annealed to that induced by surface dosing, we extract an approximate diffusion coefficient for Si in GaN of 3.5 x 10{sup -18} cm{sup 2}/s at 810{sup o}C.

Munkholm, A.; Stephenson, G. B.; Eastman, J. A.; Auciello, O.; Murty, M. V. R.; Thompson, C.; Fini, P.; Speck, J. S.; DenBaars, S. P.; Northern Illinois Univ.; Univ. of California at Santa Barbara

2000-12-01T23:59:59.000Z

195

Millimeter-wave GaN high electron mobility transistors and their integration with silicon electronics  

E-Print Network [OSTI]

In spite of the great progress in performance achieved during the last few years, GaN high electron mobility transistors (HEMTs) still have several important issues to be solved for millimeter-wave (30 ~ 300 GHz) applications. ...

Chung, Jinwook W. (Jinwook Will)

2011-01-01T23:59:59.000Z

196

Amorphization Processes in Au Ion Irradiated GaN at 150 - 300...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and small crystalline zones that are randomly oriented. Citation: Jiang W, WJ Weber, LM Wang, and K Sun.2004."Amorphization Processes in Au Ion Irradiated GaN at 150 - 300...

197

Thermal annealing characteristics of Si and Mg-implanted GaN thin films  

SciTech Connect (OSTI)

In this letter, we report the results of ion implantation of GaN using {sup 28}Si and {sup 24}Mg species. Structural and electrical characterizations of the GaN thin films after thermal annealing show that native defects in the GaN films dominate over implant doping effects. The formation energies of the annealing induced defects are estimated to range from 1.4 to 3.6 eV. A 40 keV 10{sup 14} cm{sup {minus}2} Mg implant results in the decrease of the free-carrier concentration by three orders of magnitude compared to unimplanted GaN up to an annealing temperature of 690{degree}C. Furthermore, we have observed the correlation between these annealing-induced defects to both improved optical and electrical properties. {copyright} {ital 1996 American Institute of Physics.}

Chan, J.S.; Cheung, N.W. [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)] [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States); Schloss, L.; Jones, E.; Wong, W.S.; Newman, N.; Liu, X.; Weber, E.R. [Department of Material Science and Mineral Engineering, University of California, Berkeley, California 64720 (United States)] [Department of Material Science and Mineral Engineering, University of California, Berkeley, California 64720 (United States); Gassman, A.; Rubin, M.D. [Lawrence Berkeley Laboratory, 1 Cyclotron Road, University of California, Berkeley, California 64720 (United States)] [Lawrence Berkeley Laboratory, 1 Cyclotron Road, University of California, Berkeley, California 64720 (United States)

1996-05-01T23:59:59.000Z

198

In-situ ellipsometry: Identification of surface terminations during GaN growth , T. Schmidtling1  

E-Print Network [OSTI]

1 In-situ ellipsometry: Identification of surface terminations during GaN growth C. Cobet1 , T SE, one is not limited to any special bulk or surface symmetry for optical characterisation. In PAMBE

Feenstra, Randall

199

JOURNAL OF MATERIALS SCIENCE 40 (2005) 2101 2103 LETTERS Pressureless sintering of silicon nitride/boron nitride  

E-Print Network [OSTI]

, West Lafayette, Indiana 47907-2044, USA Silicon nitride (Si3N4) and boron nitride (BN) are ma- terials2O3 (Alcoa A- 16SG, 0.4 Āµm in diameter) and 4 wt% Y2O3 (Alfa Aesar REacton, 10 Āµm in diameter

Trice, Rodney W.

200

K.K. Gan ATLAS Pixel Week 1 New Results on Opto-Electronics  

E-Print Network [OSTI]

University #12;K.K. Gan ATLAS Pixel Week 2 Outline l VDC-I5 l VDC/DORIC-I5e l QA l BeO Opto-board l Summary reset from active high to low for ease of implementation by DCS ] slightly better performance at Ā±3s: Engineering Run #12;K.K. Gan ATLAS Pixel Week 9 l circuit boards: designed/built/tested l LabView programs

Gan, K. K.

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
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201

By Deborah A. Kramer No gallium production was reported in the McDonnell Douglas Corp. reportedly will world producers were Australia, Germany, and  

E-Print Network [OSTI]

facility in optoelectronic devices [light-emitting diodes France from stockpiled crude gallium produced, and in 1994. Although the total quantity of gallium used in optoelectronic devices increased, its percentage

202

The Mg impurity in nitride alloys  

SciTech Connect (OSTI)

Although several magnetic resonance studies address the Mg acceptor in GaN, there are few reports on Mg doping in the alloys, where hole production depends strongly on the Al or In content. Our electron paramagnetic resonance (EPR) measurements of the p-type alloys suggest that the Mg impurity retains the axial symmetry, characteristic of a p-type dopant in both alloys; however, In and Al produce additional, different characteristics of the acceptor. In InGaN, the behavior is consistent with a lowering of the acceptor level and increasing hole density as In concentration increases. For AlGaN, the amount of neutral Mg decreases with increasing Al content, which is attributed to different kinetics of hydrogen diffusion thought to occur in samples with higher Al mole fraction.

Zvanut, M. E.; Willoughby, W. R.; Sunay, U. R. [Department of Physics, University of Alabama at Birmingham, Birmingham AL (United States); Koleske, D. D.; Allerman, A. A. [Sandia National Laboratory, Albuquerque NM (United States); Wang, Ke; Araki, Tsutomu [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga (Japan); Nanishi, Yasushi [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga, Japan and WCU Program, Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of)

2014-02-21T23:59:59.000Z

203

Nanowire-templated lateral epitaxial growth of non-polar group III nitrides  

DOE Patents [OSTI]

A method for growing high quality, nonpolar Group III nitrides using lateral growth from Group III nitride nanowires. The method of nanowire-templated lateral epitaxial growth (NTLEG) employs crystallographically aligned, substantially vertical Group III nitride nanowire arrays grown by metal-catalyzed metal-organic chemical vapor deposition (MOCVD) as templates for the lateral growth and coalescence of virtually crack-free Group III nitride films. This method requires no patterning or separate nitride growth step.

Wang, George T. (Albuquerque, NM); Li, Qiming (Albuquerque, NM); Creighton, J. Randall (Albuquerque, NM)

2010-03-02T23:59:59.000Z

204

 

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Defect-Driven Magnetism in Mn-doped GaN Defect-Driven Magnetism in Mn-doped GaN Semiconductors doped with magnetic elements are very interesting materials. In these materials, the magnetic impurities interact with and induce magnetism in the semiconductor host. Thus, they have the potential for combining magnetism with the rich electronic behavior of semiconductors, which may lead to new generations of low-power-consumption electronics, non-volatile memories, and field-configurable logic devices. Gallium nitride doped with Mn is particularly interesting because it is one of the few materials for which magnetism above room temperature has been reported, making it a candidate room-temperature magnetic semiconductor. Photo: Gan Molecules Illustration of the crystal structures derived from x-ray results and calculations. In ideal GaN (left), a Mn atom substitutes

205

Roughening surface morphology on free-standing GaN membrane with laser lift-off technique  

Science Journals Connector (OSTI)

An ultraviolet (UV) laser lift-off (LLO) technique was presented to form a roughened surface morphology on GaN membrane grown by...

Ting Wang; Xia Guo; Yuan Fang; GuangDi Shen

2007-04-01T23:59:59.000Z

206

Cordierite silicon nitride filters. Final report  

SciTech Connect (OSTI)

The objective of this project was to develop a silicon nitride based crossflow filter. This report summarizes the findings and results of the project. The project was phased with Phase I consisting of filter material development and crossflow filter design. Phase II involved filter manufacturing, filter testing under simulated conditions and reporting the results. In Phase I, Cordierite Silicon Nitride (CSN) was developed and tested for permeability and strength. Target values for each of these parameters were established early in the program. The values were met by the material development effort in Phase I. The crossflow filter design effort proceeded by developing a macroscopic design based on required surface area and estimated stresses. Then the thermal and pressure stresses were estimated using finite element analysis. In Phase II of this program, the filter manufacturing technique was developed, and the manufactured filters were tested. The technique developed involved press-bonding extruded tiles to form a filter, producing a monolithic filter after sintering. Filters manufactured using this technique were tested at Acurex and at the Westinghouse Science and Technology Center. The filters did not delaminate during testing and operated and high collection efficiency and good cleanability. Further development in areas of sintering and filter design is recommended.

Sawyer, J.; Buchan, B. [Acurex Environmental Corp., Mountain View, CA (United States); Duiven, R.; Berger, M. [Aerotherm Corp., Mountain View, CA (United States); Cleveland, J.; Ferri, J. [GTE Products Corp., Towanda, PA (United States)

1992-02-01T23:59:59.000Z

207

Hafnium nitride for hot carrier solar cells  

Science Journals Connector (OSTI)

Abstract Hot carrier solar cells is an attractive technology with the potential of reaching high energy conversion efficiencies approaching the thermodynamic limit of infinitely stacked multi-junction solar cells: 65% under one sun and 86% under maximally concentrated. The hot carrier solar cell is conceptually simple consisting of two key components: absorber and energy selective contacts. High efficiencies are achieved by minimising the energy lost to thermalisaton of hot photo-generated carriers while absorbing majority of the solar spectrum. For this to be achieved, energy selective contacts are required to allow the extraction of carriers fast enough at an energy level above the electronic band edge. It is critical for the absorber to be able to maintain a hot carrier population for a sufficiently long time period for the extraction of carriers while they are ‘hot’. Bulk materials with a large gap between acoustic and optical branches in the phonon dispersion are predicted to exhibit slow hot carrier thermalisation rates. Hafnium nitride is such a material with a large gap in its phonon dispersion and is identified as a potential material to be used as a hot carrier absorber. Hafnium nitride has been deposited using reactive sputtering and characterised to investigate material properties and carrier cooling rates.

Simon Chung; Santosh Shrestha; Xiaoming Wen; Yu Feng; Neeti Gupta; Hongze Xia; Pyng Yu; Jau Tang; Gavin Conibeer

2014-01-01T23:59:59.000Z

208

Vacancy Hardening and Softening in Transition Metal Carbides and Nitrides  

SciTech Connect (OSTI)

The effects of vacancies on mechanical properties of the transition metal carbides and nitrides are studied using the ab initio pseudopotential approach. Calculated shear elastic stiffness and electronic structures show that the vacancy produces entirely different effects on the mechanical strength of groups IVb nitrides and Vb carbides. It is found that the occupation of shear-unstable metallic dd bonding states changes essentially in an opposite way for the carbides and nitrides in the presence of vacancies, resulting in different responses to shear stress. Our study provides an atomistic understanding of the anomaly in hardness for these substoichiometric materials.

Jhi, Seung-Hoon; Louie, Steven G.; Cohen, Marvin L.; Ihm, Jisoon

2001-04-09T23:59:59.000Z

209

Iron-Nitride Alloy Magnets: Transformation Enabled Nitride Magnets Absent Rare Earths (TEN Mare)  

SciTech Connect (OSTI)

REACT Project: Case Western is developing a highly magnetic iron-nitride alloy to use in the magnets that power electric motors found in EVs and renewable power generators. This would reduce the overall price of the motor by eliminating the expensive imported rare earth minerals typically found in today’s best commercial magnets. The iron-nitride powder is sourced from abundant and inexpensive materials found in the U.S. The ultimate goal of this project is to demonstrate this new magnet system, which contains no rare earths, in a prototype electric motor. This could significantly reduce the amount of greenhouse gases emitted in the U.S. each year by encouraging the use of clean alternatives to oil and coal.

None

2012-01-01T23:59:59.000Z

210

Deprotecting Thioacetyl-Terminated Terphenyldithiol for Assembly on Gallium Arsenide  

SciTech Connect (OSTI)

We characterize the assembly of terphenyldithiol (TPDT) on gallium arsenide (GaAs) from ethanol (EtOH) and tetrahydrofuran (THF) as a function of ammonium hydroxide (NH4OH) concentration. NH4OH facilitates the conversion of thioacetyl end groups of the TPDT precursor to thiolates in the assembly solution. The final structure of TPDT assembled on GaAs is sensitive not only to the assembly solvent but also to NH4OH concentration. In the presence of low concentrations of NH4OH (1 mM), TPDT assemblies from EtOH are oriented upright. The same assemblies are less upright when adsorption is carried out at higher NH4OH concentrations. In THF, TPDT does not adsorb significantly on GaAs at low NH4OH concentrations. The surface coverage and structural organization of these assemblies improve with increasing NH4OH concentrations, although these assemblies are never as organized as those from EtOH. The difference in the final structure of TPDT assemblies is attributed to differences in the thiolate fraction in the assembly solution at the point of substrate immersion.

Krapchetov,D.; Ma, H.; Jen, A.; Fischer, D.; Loo, Y.

2008-01-01T23:59:59.000Z

211

Analytic bond-order potential for the gallium arsenide system  

Science Journals Connector (OSTI)

An analytic, bond-order potential (BOP) is proposed and parametrized for the gallium arsenide system. The potential addresses primary (?) and secondary (?) bonding and the valence-dependent character of heteroatomic bonding, and it can be combined with an electron counting potential to address the distribution of electrons on the GaAs surface. The potential was derived from a tight-binding description of covalent bonding by retaining the first two levels of an expanded Green’s function for the ? and ? bond-order terms. Predictions using the potential were compared with independent estimates for the structures and binding energy of small clusters (dimers, trimers, and tetramers) and for various bulk lattices with coordinations varying from 4 to 12. The structure and energies of simple point defects and melting transitions were also investigated. The relative stabilities of the (001) surface reconstructions of GaAs were well predicted, especially under high-arsenic-overpressure conditions. The structural and binding energy trends of this GaAs BOP generally match experimental observations and ab initio calculations.

D. A. Murdick; X. W. Zhou; H. N. G. Wadley; D. Nguyen-Manh; R. Drautz; D. G. Pettifor

2006-01-20T23:59:59.000Z

212

Change in the current-carrier concentration upon doping PbTe with gallium  

SciTech Connect (OSTI)

Upon doping PbTe with gallium, both high-resistivity samples with intrinsic conductivity and low-resistivity samples with electronic conductivity (n/sub e/ = 10/sup 18/ cm/sup -3/) are produced on the PbTe-GaTe section. A thorough investigation of the dependence of the thermo-emf of Pb/sub 1-x/Ga/sub x/Te on the excess Pb and Te side showed the presence of a wide region with intrinsic conductivity. The experimental data can be explained by the fact that impure gallium in PbTe has negative Hubbard energy and stabilizes the Fermi level almost at the center of the forbidden band. At high gallium concentrations, Ga/sub 2/Te/sub 3/ precipitates at first, and then GaTe precipitates as well. The lead forming in excess transforms Ga/sup 3 +/ to Ga/sup +/, which produces the electronic conductivity in the material.

Bushmarina, G.S.; Gruzinov, B.F.; Drabkin, I.A.; Lev, E.Ya.; Moizhes, B.Ya; Suprun, S.G.

1987-07-01T23:59:59.000Z

213

Sandia National Laboratories: III-Nitride core-shell nanowire...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sector III-Nitride core-shell nanowire arrayed solar cells On April 27, 2012, in Energy, Energy Efficiency, News, News & Events, Solid-State Lighting In a new EFRC-supported...

214

Journal of Crystal Growth 293 (2006) 273277 A study of semi-insulating GaN grown on AlN buffer/sapphire  

E-Print Network [OSTI]

-temperature GaN interlayer. In comparison with the normal GaN grown on sapphire, the crystal quality measurement results of GaN grown directly on an AlN buffer indicated that the as-grown-undoped Ga, or high density of edge-type dislocations [6Ā­10]. However, Fe and other heavy metals tend to have reactor

Ozbay, Ekmel

215

Molybdenum enhanced low-temperature deposition of crystalline silicon nitride  

DOE Patents [OSTI]

A process for chemical vapor deposition of crystalline silicon nitride is described which comprises the steps of: introducing a mixture of a silicon source, a molybdenum source, a nitrogen source, and a hydrogen source into a vessel containing a suitable substrate; and thermally decomposing the mixture to deposit onto the substrate a coating comprising crystalline silicon nitride containing a dispersion of molybdenum silicide. 5 figures.

Lowden, R.A.

1994-04-05T23:59:59.000Z

216

Gallium diffusion into self-assembled InAs quantum dots grown on indium phosphide substrates  

SciTech Connect (OSTI)

The photoluminescence spectrum of small self-assembled In(Ga)As quantum dots grown on InP substrates is composed of distinct spectral lines. These lines correspond to monolayer variations in the dots smallest dimension: their heights. We use this phenomenon in order to study the diffusion of gallium atoms into the self-assembled quantum dots. We demonstrate that substantial amounts of gallium atoms diffuse from a strained GaInP layer underneath the quantum dots into the quantum dots.

Raz, T.; Shuall, N.; Bahir, G.; Ritter, D.; Gershoni, D.; Chu, S.N.G. [Department of Electrical Engineering, Technion - Israel Institute of Technology, Technion City, Haifa 32000 (Israel); Physics Department and The Solid State Institute, Technion - Israel Institute of Technology, Technion City, Haifa 32000 (Israel); Multiplex, Inc., 5000 Hadley Rd., South Plainfield, New Jersey 07080 (United States)

2004-10-18T23:59:59.000Z

217

A boron nitride nanotube peapod thermal rectifier  

SciTech Connect (OSTI)

The precise guidance of heat from one specific location to another is paramount in many industrial and commercial applications, including thermal management and thermoelectric generation. One of the cardinal requirements is a preferential conduction of thermal energy, also known as thermal rectification, in the materials. This study introduces a novel nanomaterial for rectifying heat—the boron nitride nanotube peapod thermal rectifier. Classical non-equilibrium molecular dynamics simulations are performed on this nanomaterial, and interestingly, the strength of the rectification phenomenon is dissimilar at different operating temperatures. This is due to the contingence of the thermal flux on the conductance at the localized region around the scatterer, which varies with temperature. The rectification performance of the peapod rectifier is inherently dependent on its asymmetry. Last but not least, the favourable rectifying direction in the nanomaterial is established.

Loh, G. C., E-mail: jgloh@mtu.edu [Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States); Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 (Singapore); Baillargeat, D. [CNRS-International-NTU-Thales Research Alliance (CINTRA), 50 Nanyang Drive, Singapore 637553 (Singapore)

2014-06-28T23:59:59.000Z

218

Transport properties, specific heat and thermal conductivity of GaN nanocrystalline ceramic  

SciTech Connect (OSTI)

The structural and transport properties (resistivity, thermopower and Hall effect), specific heat and thermal conductivity have been measured for GaN nanocrystalline ceramic prepared by hot pressing. It was found that the temperature dependence of resistivity in temperature range 10-300 K shows the very low activation energy, which is ascribed to the shallow donor doping originating in amorphous phase of sample. The major charge carriers are electrons, what is indicated by negative sign of Hall constant and Seebeck coefficient. The thermopower attains large values (-58 {mu}V/K at 300 K) and was characterized by linear temperature dependence which suggests the diffusion as a major contribution to Seebeck effect. The high electron concentration of 1.3x10{sup 19} cm{sup -3} and high electronic specific heat coefficient determined to be 2.4 mJ/molK{sup 2} allow to conclude that GaN ceramic demonstrates the semimetallic-like behavior accompanied by very small mobility of electrons ({approx}0.1 cm{sup 2}/V s) which is responsible for its high resistivity. A low heat conductivity of GaN ceramics is associated with partial amorphous phase of GaN grains due to high pressure sintering. - Graphical Abstract: Thermal resistivity and thermopower measurements indicates the high phonon scattering and lack of phonon-drag contribution to thermopower in GaN nanoceramics pressed under 4 GPa at 800 {sup o}C.

Sulkowski, Czeslaw [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); ChuchmaLa, Andrzej, E-mail: andrzej.chuchmala@pwr.wroc.p [Wroclaw University of Technology, Institute of Electrical Engineering Fundamentals (I7), Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Zaleski, Andrzej J.; Matusiak, Marcin; Mucha, Jan; GLuchowski, PaweL; Strek, WiesLaw [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland)

2010-10-15T23:59:59.000Z

219

Direct measurement of curvature dependent ion etching of GaN Bentao Cui and P.I. Cohen  

E-Print Network [OSTI]

Direct measurement of curvature dependent ion etching of GaN Bentao Cui and P.I. Cohen Department of Electrical and Computer Engineering and Department of Chemical Engineering and Materials Science, University of nanoscale pores or dimples during ion etching of GaN was used to measure the magnitude of the curvature

Cohen, Philip I.

220

Millimeter wave ferromagnetic resonance in gallium-substituted ?-iron oxide  

SciTech Connect (OSTI)

In millimeter wave frequency range, hexagonal ferrites with high uniaxial anisotropic magnetic fields are used as absorbers. These ferrites include M-type barium ferrite (BaFe{sub 12}O{sub 19}) and strontium ferrite (SrFe{sub 12}O{sub 19}), which have natural ferromagnetic resonant frequency range from 40 GHz to 60?GHz. However, the higher frequency range lacks suitable materials that support the higher frequency ferromagnetic resonance. A new series of gallium-substituted ?-iron oxides (?-Ga{sub x}Fe{sub 2?x}O{sub 3}) are synthesized which have ferromagnetic resonant frequencies appearing over the frequency range 30 GHz–150 GHz. The ?-Ga{sub x}Fe{sub 2?x}O{sub 3} is synthesized by the combination of reverse micelle and sol-gel techniques or the sol-gel method only. The particle sizes are observed to be smaller than 100 nm. In this paper, the free space magneto-optical approach has been employed to study these newly developed ?-Ga{sub x}Fe{sub 2?x}O{sub 3} particles in millimeter waves. This technique enables to obtain precise transmission spectra to determine the dielectric and magnetic properties of both isotropic and anisotropic ferrites in the millimeter wave frequency range from a single set of direct measurements. The transmittance and absorbance spectra of ?-Ga{sub x}Fe{sub 2?x}O{sub 3} are shown in this paper. Strong ferromagnetic resonances at different frequencies determined by the x parameter are found.

Chao, Liu, E-mail: liu.chao@tufts.edu; Afsar, Mohammed N. [Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155 (United States); Ohkoshi, Shin-ichi [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2014-05-07T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Protective nitride formation on stainless steel alloys for proton exchange membrane fuel cell bipolar plates  

SciTech Connect (OSTI)

Gas nitridation has shown excellent promise to form dense, electrically conductive and corrosion-resistant Cr-nitride surface layers on Ni-Cr base alloys for use as proton exchange membrane fuel cell (PEMFC) bipolar plates. Due to the high cost of nickel, Fe-base bipolar plate alloys are needed to meet the cost targets for many PEMFC applications. Unfortunately, nitridation of Fe-base stainless steel alloys typically leads to internal Cr-nitride precipitation rather than the desired protective surface nitride layer formation, due to the high permeability of nitrogen in these alloys. This paper reports the finding that it is possible to form a continuous, protective Cr-nitride (CrN and Cr{sub 2}N) surface layer through nitridation of Fe-base stainless steel alloys. The key to form a protective Cr-nitride surface layer was found to be the initial formation of oxide during nitridation, which prevented the internal nitridation typically observed for these alloys, and resulted in external Cr-nitride layer formation. The addition of V to the alloy, which resulted in the initial formation of V{sub 2}O{sub 3}-Cr{sub 2}O{sub 3}, was found to enhance this effect, by making the initially formed oxide more amenable to subsequent nitridation. The Cr-nitride surface layer formed on model V-modified Fe-27Cr alloys exhibited excellent corrosion resistance and low interfacial contact resistance under simulated PEMFC bipolar plate conditions.

Yang, Bing [ORNL; Brady, Michael P [ORNL; Wang, Heli [National Renewable Energy Laboratory (NREL); Turner, John [National Renewable Energy Laboratory (NREL); More, Karren Leslie [ORNL; Young, David J [ORNL; Tortorelli, Peter F [ORNL; Payzant, E Andrew [ORNL; Walker, Larry R [ORNL

2007-01-01T23:59:59.000Z

222

Effect of buffer layer growth temperature on epitaxial GaN films deposited by magnetron sputtering  

SciTech Connect (OSTI)

Epitaxial GaN films were deposited by reactive sputtering of a GaAs target in 100 % nitrogen at 700 deg. C on ZnO buffer layers grown at different substrate temperatures over sapphire substrates. High resolution X-ray diffraction measurements and the corresponding analysis show that the growth temperature of buffer layers significantly affects the micro-structural parameters of GaN epilayer, such as lateral coherence length, tilt and twist, while the vertical coherence length remains unaffected. The optimum substrate temperature for buffer layer growth has been found to be 300 deg. C. High epitaxial quality GaN film grown on such a buffer layer exhibited micro strain of 1.8x10{sup -4} along with screw and edge type dislocation densities of 7.87x10{sup 9} and 1.16x10{sup 11}, respectively.

Mohanta, P.; Singh, D.; Kumar, R.; Ganguli, T.; Srinivasa, R. S.; Major, S. S. [Center For Research in Nano-Technology and Science (India); Semiconductor Laser Section, RRCAT, Indore-452013 (India); Department of Metallurgical Engineering and Materials Science (India); Department of Physics, Indian Institute of Technology Bombay, Mumbai - 400076 (India)

2012-06-05T23:59:59.000Z

223

Green light emitting diode grown on thick strain-reduced GaN template  

Science Journals Connector (OSTI)

Abstract We report a green light-emitting diode (LED) grown on thick strain-reduced GaN template. As the injection current changes from 20 mA to 120 mA, blue-shift of EL peak wavelength reduces from 9.3 nm for the LED on sapphire substrate to 6.8 nm for the LED grown on thick strain-reduced GaN template. Furthermore, the light output power and external quantum efficiency of the LED on thick strain-reduced GaN template are respectively 1.48 mW and 2.5% at the forward current of 20 mA, which is twice as much as the LED on sapphire substrate. In contrast, the reverse current is 2 ?A lower than that of the LED on the sapphire at ?8 V.

Jiankun Yang; Tongbo Wei; Qiang Hu; Ziqiang Huo; Baojuan Sun; Ruifei Duan; Junxi Wang

2015-01-01T23:59:59.000Z

224

Physical Properties of GaN Nanotubes as Revealed by Computer Simulation  

SciTech Connect (OSTI)

Single-crystalline wurtzite GaN nanotubes have been synthesized recently with proposed applications in nanoscale electronics, optoelectronics and the biochemical-sensing field. Molecular dynamics methods with a Stillinger-Weber potential are used to investigate the melting behavior, thermal conductivity and mechanical properties of these wurtzite-type single crystalline GaN nanotubes. Four major topical areas are summarized in this chapter. (1) The melting temperature of the GaN nanotubes increases with the thickness of the nanotubes to a saturation value, which is close to the melting temperature of bulk GaN. The simulations result reveal that the nanotubes begin to melt at the surface, and then the melting rapidly extends to the interior of the nanotubes as the temperature increases. (2) The thermal conductivity of nanotubes is smaller than that of the bulk GaN single crystal. The thermal conductivity is also found to decrease with temperature and increase with increasing wall thickness of the nanotubes. The change of phonon spectrum and surface inelastic scattering may account for the reduction of thermal conductivity in the nanotubes, while thermal softening and high frequency phonon interactions at high temperatures may provide an explanation for its decrease with increasing temperature. (3) At low temperatures, the simulation results show that the nanotubes exhibit brittle properties; whereas at high temperatures, they behave as ductile materials. The brittle to ductile transition temperature generally increases with increasing wall thickness of the nanotubes and increasing strain rate. (4) The simulation temperature, tube length and strain rate affect the buckling behavior of GaN nanotubes. The critical stress decreases with the increase of simulation temperature and tube length. The dependence of buckling on tube length is consistent with the analysis of equivalent continuum structures using Euler buckling theory.

Wang, Zhiguo; Gao, Fei; Zu, Xiaotao; Weber, William J.

2008-07-25T23:59:59.000Z

225

E-Print Network 3.0 - amorphous carbon nitride Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

-8984(99)96581-5 Structural and magnetic properties of ammonia-nitrided Y2Fe17 N X Shen, J I Budnick, W A Hines, Y D Zhang, D... and magnetic properties of ammonia-nitrided...

226

Synthesis of III-V nitride nanowires with controlled structure, morphology, and composition  

E-Print Network [OSTI]

The III-V nitride materials system offers tunable electronic and optical properties that can be tailored for specific electronic and optoelectronic applications by varying the (In,Ga,Al)N alloy composition. While nitride ...

Crawford, Samuel Curtis

2014-01-01T23:59:59.000Z

227

Surface engineering and chemical characterization in ion-nitrided titanium and titanium alloys  

Science Journals Connector (OSTI)

The chemical and physical characteristics of ion-nitrided surface layers, obtained on ?-? titanium alloys, are examined and correlated both with the working conditions adopted in the ion-nitriding process and wit...

T. Bacci; G. Pradelli; B. Tesi; C. Gianoglio; C. Badini

1990-10-01T23:59:59.000Z

228

Investigation of Gallium Partitioning Behavior in Aqueous Two-Phase Systems Containing Polyethylene Glycol and Ammonium Sulfate  

Science Journals Connector (OSTI)

Gallium is assumed to be an indispensable rare metal mainly because of its fast growing demand as gallium arsenide (GaAs) in integrated circuits. ... Traditional extraction methods for gallium usually are organic?water two-phase systems, which involve volatile, flammable, and explosive organic solvents, such as n-hexane, toluene, xylene, benzene, nitrobenzene and kerosene. ... (17) A temperature increase reduces the mutual solubility of the two phases and results in an increase of PEG concentration in the upper phase and of volume in the lower phase, which all make ?w1 increase. ...

Yuhuan Chen; Xiaoli Liu; Yan Lu; Xiuying Zhang

2009-04-22T23:59:59.000Z

229

Optical, electrical, and solar energy-conversion properties of gallium arsenide nanowire-array  

E-Print Network [OSTI]

Optical, electrical, and solar energy-conversion properties of gallium arsenide nanowire, and will aid in the design and optimization of nanowire-based systems for solar energy-conversion applications, and the photoelectrochemical energy-conversion properties of GaAs nanowire arrays were evaluated in contact with one

Zhou, Chongwu

230

Molten Gallium as a Catalyst for the Large-Scale Growth of Highly Aligned Silica Nanowires  

E-Print Network [OSTI]

Molten Gallium as a Catalyst for the Large-Scale Growth of Highly Aligned Silica Nanowires Zheng a small size (5-100 nm in diameter), high melting point metal (such as gold and iron) catalyst particle as an effective catalyst for the large-scale growth of highly aligned, closely packed silica nanowire bunches

Wang, Zhong L.

231

GALLIUM--2003 28.1 References that include a section mark () are found in the Internet  

E-Print Network [OSTI]

in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic devices (LEDs, laser diodes, photodetectors, and solar cells) and ICs. ICs and optoelectronic devices each accounted for 41) and optoelectronic devices [mostly laser diodes and light- emitting diodes (LEDs)]. Estimated crude gallium

232

CX-009000: Categorical Exclusion Determination | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

0: Categorical Exclusion Determination 0: Categorical Exclusion Determination CX-009000: Categorical Exclusion Determination "High Quality, Low Cost Bulk Gallium Nitride (GaN) Substrates Grown by the Electrochemical Solution Growth Method CX(s) Applied: A9, B3.6 Date: 08/20/2012 Location(s): Missouri Offices(s): Golden Field Office The U.S. Department of Energy (DOE) is proposing to provide federal funding to MEMC Electronic Materials, Inc. MEMC would conduct research and development activities for a two phase project to develop a new process method for growing large bulk gallium nitrate (GaN) crystals at low cost with improved functional properties." CX-009000.pdf More Documents & Publications CX-000845: Categorical Exclusion Determination Energy Storage Systems 2010 Update Conference Presentations - Day 3,

233

Lattice dynamics of GaN: Effects of 3d electrons  

Science Journals Connector (OSTI)

We perform first-principles calculations of structural, dielectric, and lattice-dynamical properties of cubic GaN. The equilibrium structure is obtained using the plane-wave pseudopotential approach within the density-functional theory and local-density approximation. The dielectric and vibrational properties are computed within the density-functional perturbation theory. The effect of the Ga 3d electrons is treated by taking into account the nonlinear core corrections for the exchange and correlation energy. The importance of 3d electrons for the bonding strength is determined, and their influence on the dielectric and dynamical properties of GaN is analyzed and discussed.

K. Karch; F. Bechstedt; T. Pletl

1997-08-15T23:59:59.000Z

234

Partially filled intermediate band of Cr-doped GaN films  

SciTech Connect (OSTI)

We investigated the band structure of sputtered Cr-doped GaN (GaCrN) films using optical absorption, photoelectron yield spectroscopy, and charge transport measurements. It was found that an additional energy band is formed in the intrinsic band gap of GaN upon Cr doping, and that charge carriers in the material move in the inserted band. Prototype solar cells showed enhanced short circuit current and open circuit voltage in the n-GaN/GaCrN/p-GaN structure compared to the GaCrN/p-GaN structure, which validates the proposed concept of an intermediate-band solar cell.

Sonoda, S. [Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585 (Japan)

2012-05-14T23:59:59.000Z

235

K.K. Gan ATLAS Tracker Upgrade Workshop 1 Nov 5, 2008  

E-Print Network [OSTI]

channel Preliminary #12;K.K. Gan ATLAS Tracker Upgrade Workshop 8 Radiation-Hardness of GaAs PIN AOC.03 AOC 5.0 0.60 0.04 Optowell 3.125 0.60 0.10 Hamamatsu G8921 2.5 0.50 0.20 Si Taiwan 1.0 0.55 0 irradiation with SLHC dose: AOC(5 & 10 G) have good power #12;K.K. Gan ATLAS Tracker Upgrade Workshop 12

Gan, K. K.

236

Selective etching of dislocations in GaN grown by low-pressure solution growth  

Science Journals Connector (OSTI)

This work presents an experimental study on the identification and quantification of different types of dislocations in GaN grown by low-pressure solution growth. A reliable defect selective etching procedure in a NaOH-KOH melt is developed and validated using transmission electron microscopy that permits to define groups of etch pits that belong each to dislocations with a specific Burgers vector. This way a comparably fast method is provided for determining the total, the specific dislocation densities and the type of dislocation in a statistically representative way. The results for the solution grown samples are compared to those obtained for MOCVD GaN.

I.Y. Knoke; P. Berwian; E. Meissner; J. Friedrich; H.P. Strunk; G. Müller

2010-01-01T23:59:59.000Z

237

Ge doped GaN with controllable high carrier concentration for plasmonic applications  

SciTech Connect (OSTI)

Controllable Ge doping in GaN is demonstrated for carrier concentrations of up to 2.4?×?10{sup 20} cm{sup ?3}. Low temperature luminescence spectra from the highly doped samples reveal band gap renormalization and band filling (Burstein-Moss shift) in addition to a sharp transition. Infrared ellipsometry spectra demonstrate the existence of electron plasma with an energy around 3500?cm{sup ?1} and a surface plasma with an energy around 2000?cm{sup ?1}. These findings open possibilities for the application of highly doped GaN for plasmonic devices.

Kirste, Ronny; Hoffmann, Marc P.; Sachet, Edward; Bobea, Milena; Bryan, Zachary; Bryan, Isaac; Maria, Jon-Paul; Collazo, Ramón; Sitar, Zlatko [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States)] [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States); Nenstiel, Christian; Hoffmann, Axel [Institut f?r Festkörperphsyik, TU-Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany)] [Institut f?r Festkörperphsyik, TU-Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany)

2013-12-09T23:59:59.000Z

238

Thermodynamic stability of oxide, nitride, and carbide coating materials in liquid Sn25Li  

E-Print Network [OSTI]

Thermodynamic stability of oxide, nitride, and carbide coating materials in liquid SnĀ­25Li S of various oxides, carbides, and nitrides in SnĀ­Li is estimated as a function of lithium composition K most of the studied nitrides, carbides, and some oxides were found to be stable (DrG > 0). However

Ghoniem, Nasr M.

239

Trends in elasticity and electronic structure of transition-metal nitrides and carbides from first principles  

E-Print Network [OSTI]

Trends in elasticity and electronic structure of transition-metal nitrides and carbides from first 2005 The elastic properties of selected transition-metal TM nitrides and carbides in B1 structure the transition-metal nitrides and carbides remain unclear and a challenge for engineering hard materials

Wu, Zhigang

240

Extreme nitriding limits in aluminium extrusion  

Science Journals Connector (OSTI)

Extrusion of aluminium is an efficient manufacturing process which allows long continuous production. The heated billet (aluminium material) is squeezed through the opening of a metal die in order to shape the desired aluminium profile. A long continuous production increases aging of the die and hampers its capability to yield homogeneously shaped profiles. Hence the dies are usually removed from production lines before their breaking point and only go back into production after receiving a layer coat for protection of the metal. This paper consists of a preliminary analysis of the extrusion amounts between consecutive maintenance procedures of the dies. A maintenance procedure in its whole encompasses an immersion bath of the die in caustic soda, a polishing operation and possibly a subsequent coat layering process in a nitriding chamber. The main goal here is to find the optimal life cycle for a die, in the sense that we are looking for a risk level (an extrusion amount) above which die-damage occurs with a certain high probability. We shall rely on extreme value statistics to answer the question of how long can we go on at each continuous operation of aluminium extrusion.

Claudia Neves; M. Ivette Gomes; Isabel Fraga Alves

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Ultra-thin ohmic contacts for p-type nitride light emitting devices  

DOE Patents [OSTI]

A flip-chip semiconductor based Light Emitting Device (LED) can include an n-type semiconductor substrate and an n-type GaN epi-layer on the substrate. A p-type GaN epi-layer can be on the n-type GaN epi-layer and a metal ohmic contact p-electrode can be on the p-type GaN epi-layer, where the metal ohmic contact p-electrode can have an average thickness less than about 25 .ANG.. A reflector can be on the metal ohmic contact p-electrode and a metal stack can be on the reflector. An n-electrode can be on the substrate opposite the n-type GaN epi-layer and a bonding pad can be on the n-electrode.

Raffetto, Mark; Bharathan, Jayesh; Haberern, Kevin; Bergmann, Michael; Emerson, David; Ibbetson, James; Li, Ting

2014-06-24T23:59:59.000Z

242

Active Control of Nitride Plasmonic Dispersion in the Far Infrared.  

SciTech Connect (OSTI)

We investigate plasmonic structures in nitride-based materials for far-infrared (IR) applications. The two dimensional electron gas (2DEG) in the GaN/AlGaN material system, much like metal- dielectric structures, is a patternable plasmonic medium. However, it also permits for direct tunability via an applied voltage. While there have been proof-of-principle demonstrations of plasma excitations in nitride 2DEGs, exploration of the potential of this material system has thus far been limited. We recently demonstrated coherent phenomena such as the formation of plasmonic crystals, strong coupling of tunable crystal defects to a plasmonic crystal, and electromagnetically induced transparency in GaAs/AlGaAs 2DEGs at sub-THz frequencies. In this project, we explore whether these effects can be realized in nitride 2DEG materials above 1 THz and at temperatures exceeding 77 K.

Shaner, Eric A.; Dyer, Gregory Conrad; Seng, William Francis; Bethke, Donald Thomas; Grine, Albert Dario,; Baca, Albert G.; Allerman, Andrew A.

2014-11-01T23:59:59.000Z

243

Low temperature thermal transport in partially perforated silicon nitride membranes.  

SciTech Connect (OSTI)

The thermal transport in partially trenched silicon nitride membranes has been studied in the temperature range from 0.3 to 0.6 K, with the transition edge sensor (TES), the sole source of membrane heating. The test configuration consisted of Mo/Au TESs lithographically defined on silicon nitride membranes 1 {micro}m thick and 6 mm{sup 2} in size. Trenches with variable depth were incorporated between the TES and the silicon frame in order to manage the thermal transport. It was shown that sharp features in the membrane surface, such as trenches, significantly impede the modes of phonon transport. A nonlinear dependence of thermal resistance on trench depth was observed. Partial perforation of silicon nitride membranes to control thermal transport could be useful in fabricating mechanically robust detector devices.

Yefremenko, V.; Wang, G.; Novosad, V.; Datesman, A.; Pearson, J.; Divan, R.; Chang, C. L.; Downes, T. P.; Mcmahon, J. J.; Bleem, L. E.; Crites, A. T.; Meyer, S. S.; Carlstrom, J. E.; Univ. of Chicago

2009-05-04T23:59:59.000Z

244

K.K. Gan Group B Meeting 1 VCSEL/PIN irradiation in pre-qualification  

E-Print Network [OSTI]

/vendor VCSEL: AOC 10 Gb/s, AOC 5 Gb/s, Optowell (2.5 Gb/s) GaAs PIN: try to order 12-channel Hamamatsu bare "need custom alignment Control Sample of PIN #12;K.K. Gan Group B Meeting 4 AOC 10 Gb/s? 12

Gan, K. K.

245

K.K. Gan RD07 1 Radiation-Hard Optical Link for SLHC  

E-Print Network [OSTI]

arrays have very good optical power Optowell AOC ULM 10GULM 5G Pre-irrad #12;K.K. Gan RD07 12 Optowell 71 to SLHC dosage more VCSELs might survive with more annealing during irradiation SLHC AOC 71 MRad 0.0 0

Gan, K. K.

246

Optimal Decentralized Protocol for Electric Vehicle Charging Lingwen Gan Ufuk Topcu Steven Low  

E-Print Network [OSTI]

Abstract-- Motivated by the power-grid-side challenges in the integration of electric vehicles, we proposeOptimal Decentralized Protocol for Electric Vehicle Charging Lingwen Gan Ufuk Topcu Steven Low a decentralized protocol for negotiating day-ahead charging schedules for electric vehicles. The overall goal

Low, Steven H.

247

Piezo-Phototronic Effect on Electroluminescence Properties of p-Type GaN Thin Films  

E-Print Network [OSTI]

significance on the practical applications of GaN in optoelectronic devices under a working environment where,9 Recent studies have shown its applications in improving the performance of optoelectronic devices based result in great influence for this most popular III-V semiconductor used in optoelectronic devices

Wang, Zhong L.

248

Reverse-bias leakage current reduction in GaN Schottky diodes by electrochemical surface treatment  

E-Print Network [OSTI]

Reverse-bias leakage current reduction in GaN Schottky diodes by electrochemical surface treatment Received 15 July 2002; accepted 27 December 2002 An electrochemical surface treatment has been developed to the large power consumption and noise levels that can be present in circuits that incorporate such devices.1

Yu, Edward T.

249

VISIBLE AND INFRARED RARE-EARTH ACTIVATED ELECTROLUMINESCENCE FROM ERBIUM DOPED GaN  

E-Print Network [OSTI]

. At the same time novel work is being conducted using rare earth elements as sources of light emission. Results. III-V semiconductors doped with rare-earth elements have also been used10VISIBLE AND INFRARED RARE-EARTH ACTIVATED ELECTROLUMINESCENCE FROM ERBIUM DOPED GaN M. Garter*, R

Steckl, Andrew J.

250

An Effective Subdivision Algorithm for Diffuse Scattering of Ray Tracing Mingming Gan1  

E-Print Network [OSTI]

Department of Electrical and Information Technology, Lund University, Lund, Sweden Contact: gan@ftw.at Abstract Accurate modeling of electromagnetic wave propagation by means of ray tracing (RT) includes by evaluating the power delay profile (PDP), delay spread and angular spread. 1 Introduction Diffuse scattering

Zemen, Thomas

251

Lattice Protein Folding With Two and Four-Body Statistical Hin Hark Gan,1  

E-Print Network [OSTI]

Lattice Protein Folding With Two and Four-Body Statistical Potentials Hin Hark Gan,1 Alexander/sequence compatibility of proteins,5,6 homology modeling,7 and protein folding simulations.8 Ā­10 Currently, most structures. Multibody potentials may help improve our understanding of the cooperativity of protein folding

Schlick, Tamar

252

Metalorganic Chemical Vapor Deposition Route to GaN Nanowires with Triangular  

E-Print Network [OSTI]

Metalorganic Chemical Vapor Deposition Route to GaN Nanowires with Triangular Cross Sections Tevye widths of 15-200 nm. Transmission electron microscopy confirmed that the wires were single as a carrier gas, was percolated through the TMG precursor and coupled with a second nitrogen line to give

Yang, Peidong

253

CX-000845: Categorical Exclusion Determination | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

0845: Categorical Exclusion Determination 0845: Categorical Exclusion Determination CX-000845: Categorical Exclusion Determination 25A2445 - Ammonothermal Bulk Gallium Nitride (GaN) Crystal Growth for Energy Efficient Lighting CX(s) Applied: B3.6 Date: 01/15/2010 Location(s): New York Office(s): Advanced Research Projects Agency - Energy This project plans to address the vast energy loss and consumption associated with conventional lighting by developing a new route to large, high-quality, single crystals of gallium nitride. These crystals will serve as substrates for light emitting diodes offering high-efficiency lighting. DOCUMENT(S) AVAILABLE FOR DOWNLOAD CX-000845.pdf More Documents & Publications CX-009889: Categorical Exclusion Determination Power Electronics Research and Development Program Plan

254

Structural studies of magnesium nitride fluorides by powder neutron diffraction  

SciTech Connect (OSTI)

Samples of ternary nitride fluorides, Mg{sub 3}NF{sub 3} and Mg{sub 2}NF have been prepared by solid state reaction of Mg{sub 3}N{sub 2} and MgF{sub 2} at 1323-1423 K and investigated by powder X-ray and powder neutron diffraction techniques. Mg{sub 3}NF{sub 3} is cubic (space group: Pm3m) and has a structure related to rock-salt MgO, but with one cation site vacant. Mg{sub 2}NF is tetragonal (space group: I4{sub 1}/amd) and has an anti-LiFeO{sub 2} related structure. Both compounds are essentially ionic and form structures in which nitride and fluoride anions are crystallographically ordered. The nitride fluorides show temperature independent paramagnetic behaviour between 5 and 300 K. - Graphical abstract: Definitive structures of the ternary magnesium nitride fluorides Mg{sub 3}NF{sub 3} and the lower temperature polymorph of Mg{sub 2}NF have been determined from powder neutron diffraction data. The nitride halides are essentially ionic and exhibit weak temperature independent paramagnetic behaviour. Highlights: Black-Right-Pointing-Pointer Definitive structures of Mg{sub 3}NF{sub 3} and Mg{sub 2}NF were determined by neutron diffraction. Black-Right-Pointing-Pointer Nitride and fluoride anions are crystallographically ordered in both structures. Black-Right-Pointing-Pointer Both compounds exhibit weak, temperature independent paramagnetic behaviour. Black-Right-Pointing-Pointer The compounds are essentially ionic with ionicity increasing with F{sup -} content.

Brogan, Michael A. [School of Chemistry, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Hughes, Robert W. [WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Smith, Ronald I. [ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX (United Kingdom); Gregory, Duncan H., E-mail: Duncan.Gregory@glasgow.ac.uk [WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

2012-01-15T23:59:59.000Z

255

Synthesis of uranium nitride and uranium carbide powder by carbothermic reduction  

SciTech Connect (OSTI)

Uranium nitride and uranium carbide are being considered as high burnup fuels in next generation nuclear reactors and accelerated driven systems for the transmutation of nuclear waste. The same characteristics that make nitrides and carbides candidates for these applications (i.e. favorable thermal properties, mutual solubility of nitrides, etc.), also make these compositions candidate fuels for space nuclear reactors. In this paper, we discuss the synthesis and characterization of depleted uranium nitride and carbide for a space nuclear reactor program. Importantly, this project emphasized that to synthesize high quality uranium nitride and carbide, it is necessary to understand the exact stoichiometry of the oxide feedstock. (authors)

Dunwoody, J.T.; Stanek, C.R.; McClellan, K.J.; Voit, S.L.; Volz, H.M. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Hickman, R.R. [NASA Marshall Space Flight Center, Huntsville, Alabama (United States)

2007-07-01T23:59:59.000Z

256

Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride  

DOE Patents [OSTI]

A process for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.

Koc, Rasit (Lakewood, CO); Glatzmaier, Gregory C. (Boulder, CO)

1995-01-01T23:59:59.000Z

257

Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride  

DOE Patents [OSTI]

A process is disclosed for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.

Koc, R.; Glatzmaier, G.C.

1995-05-23T23:59:59.000Z

258

Process for producing amorphous and crystalline silicon nitride  

DOE Patents [OSTI]

A process for producing amorphous or crystalline silicon nitride is disclosed which comprises reacting silicon disulfide ammonia gas at elevated temperature. In a preferred embodiment silicon disulfide in the form of "whiskers" or needles is heated at temperature ranging from about 900.degree. C. to about 1200.degree. C. to produce silicon nitride which retains the whisker or needle morphological characteristics of the silicon disulfide. Silicon carbide, e.g. in the form of whiskers, also can be prepared by reacting substituted ammonia, e.g. methylamine, or a hydrocarbon containing active hydrogen-containing groups, such as ethylene, with silicon disulfide, at elevated temperature, e.g. 900.degree. C.

Morgan, Peter E. D. (Thousand Oaks, CA); Pugar, Eloise A. (Newbury Park, CA)

1985-01-01T23:59:59.000Z

259

Process for producing wurtzitic or cubic boron nitride  

DOE Patents [OSTI]

Disclosed is a process for producing wurtzitic or cubic boron nitride comprising the steps of: [A] preparing an intimate mixture of powdered boron oxide, a powdered metal selected from the group consisting of magnesium or aluminum, and a powdered metal azide; [B] igniting the mixture and bringing it to a temperature at which self-sustaining combustion occurs; [C] shocking the mixture at the end of the combustion thereof with a high pressure wave, thereby forming as a reaction product, wurtzitic or cubic boron nitride and occluded metal oxide; and, optionally [D] removing the occluded metal oxide from the reaction product. Also disclosed are reaction products made by the process described.

Holt, J.B.; Kingman, D.D.; Bianchini, G.M.

1992-04-28T23:59:59.000Z

260

Process for producing wurtzitic or cubic boron nitride  

DOE Patents [OSTI]

Disclosed is a process for producing wurtzitic or cubic boron nitride comprising the steps of: [A] preparing an intimate mixture of powdered boron oxide, a powdered metal selected from the group consisting of magnesium or aluminum, and a powdered metal azide; [B] igniting the mixture and bringing it to a temperature at which self-sustaining combustion occurs; [C] shocking the mixture at the end of the combustion thereof with a high pressure wave, thereby forming as a reaction product, wurtzitic or cubic boron nitride and occluded metal oxide; and, optionally [D] removing the occluded metal oxide from the reaction product. Also disclosed are reaction products made by the process described.

Holt, J. Birch (San Jose, CA); Kingman, deceased, Donald D. (late of Danville, CA); Bianchini, Gregory M. (Livermore, CA)

1992-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Ab initio density functional theory study of non-polar (101{sup Æ}0),?(112{sup Æ}0) and semipolar (202{sup Æ}1) GaN surfaces  

SciTech Connect (OSTI)

The atomic structures of non-polar GaN(101{sup Æ}0),?(112{sup Æ}0) and semipolar GaN(202{sup Æ}1),?(202{sup Æ}1{sup Æ}) surfaces were studied using ab initio calculations within density functional theory. The bulk-like truncated (1?×?1) structure with buckled Ga-N or Ga-Ga dimers was found stable on the non-polar GaN(101{sup Æ}0) surface in agreement with previous works. Ga-N heterodimers were found energetically stable on the GaN(112{sup Æ}0)-(1?×?1) surface. The formation of vacancies and substitution site defects was found unfavorable for non-polar GaN surfaces. Semipolar GaN(202{sup Æ}1)-(1?×?1) surface unit cells consist of non-polar (101{sup Æ}0) and semipolar (101{sup Æ}1) nano-facets. The (101{sup Æ}1) nano-facets consist of two-fold coordinated atoms, which form N-N dimers within a (2?×?1) surface unit cell on a GaN(202{sup Æ}1) surface. Dimers are not formed on the GaN(202{sup Æ}1{sup Æ}) surface. The stability of the surfaces with single (101{sup Æ}0) or (101{sup Æ}1) nano-facets was analyzed. A single non-polar (101{sup Æ}0)-(1?×?1) nano-facet was found stable on the GaN(202{sup Æ}1) surface, but unstable on the GaN(202{sup Æ}1{sup Æ}) surface. A single (101{sup Æ}1) nano-facet was found unstable. Semipolar GaN surfaces with (202{sup Æ}1) and (202{sup Æ}1{sup Æ}) polarity can be stabilized with a Ga overlayer at Ga-rich experimental conditions.

Mutombo, P.; Romanyuk, O., E-mail: romanyuk@fzu.cz [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnickį 10, 16200 Prague (Czech Republic)

2014-05-28T23:59:59.000Z

262

Ultra-low resistance ohmic contacts to GaN with high Si doping concentrations grown by molecular beam epitaxy  

SciTech Connect (OSTI)

Ti/Al/Ni/Au ohmic contacts were formed on heavily doped n{sup +} metal-polar GaN samples with various Si doping concentrations grown by molecular beam epitaxy. The contact resistivity (R{sub C}) and sheet resistance (R{sub sh}) as a function of corresponding GaN free carrier concentration (n) were measured. Very low R{sub C} values (<0.09 {Omega} mm) were obtained, with a minimum R{sub C} of 0.035 {Omega} mm on a sample with a room temperature carrier concentration of {approx}5 Multiplication-Sign 10{sup 19} cm{sup -3}. Based on the systematic study, the role of R{sub C} and R{sub sh} is discussed in the context of regrown n{sup +} GaN ohmic contacts for GaN based high electron mobility transistors.

Afroz Faria, Faiza; Guo Jia; Zhao Pei; Li Guowang; Kumar Kandaswamy, Prem; Wistey, Mark; Xing Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)

2012-07-16T23:59:59.000Z

263

Preliminary results from the Russian-American gallium experiment Cr-neutrino source measurement  

SciTech Connect (OSTI)

The Russian-American Gallium Experiment has been collecting solar neutrino data since early 1990. The flux measurement of solar neutrinos is well below that expected from solar models. We discuss the initial results of a measurement of experimental efficiencies by exposing the gallium target to neutrinos from an artificial source. The capture rate of neutrinos from this source is very close to that which is expected. The result can be expressed as a ratio of the measured capture rate to the anticipated rate from the source activity. This ratio is 0.93 + 0.15, {minus}0.17 where the systematic and statistical errors have been combined. To first order the experimental efficiencies are in agreement with those determined during solar neutrino measurements and in previous auxiliary measurements. One must conclude that the discrepancy between the measured solar neutrino flux and that predicted by the solar models can not arise from an experimental artifact. 17 refs., 3 figs., 1 tab.

Elliott, S.R. [Washington Univ., Seattle, WA (United States); Abdurashitov, J.N. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. for Nuclear Research; Bowles, T.J. [Los Alamos National Lab., NM (United States)] [and others

1995-12-31T23:59:59.000Z

264

Fast neutron scattering on Gallium target at 14.8 MeV  

E-Print Network [OSTI]

Benchmarking of evaluated nuclear data libraries was performed for $\\sim 14.8$ MeV neutrons on Gallium targets. The experiments were performed at China Institute of Atomic Energy(CIAE). Solid samples of natural Gallium (3.2 cm and 6.4 cm thick) were bombarded by $\\sim 14.8$ MeV neutrons and leakage neutron energy spectra were measured at 60$^{\\circ}$ and 120$^{\\circ}$. The measured spectra are rather well reproduced by MCNP-4C simulations with the CENDL-3.1, ENDF/B-VII and JENDL-4.0 evaluated nuclear data libraries, except for the inelastic contributions around $E_{n} = 10-13$ MeV. All three libraries significantly underestimate the inelastic contributions. The inelastic contributions are further studied, using the Talys simulation code and the experimental spectra are reproduced reasonably well in the whole energy range by the Talys calculation, including the inelastic contributions.

Han, R; Chen, Z; Nie, Y; Liu, X; Zhang, S; Ren, P; Jia, B; Tian, G; Luo, F; Lin, W; Liu, J; Shi, F; Huang, M; Ruan, X; Ren, J; Zhou, Z; Huang, H; Bao, J; Zhang, K; Hu, B

2014-01-01T23:59:59.000Z

265

Fast neutron scattering on Gallium target at 14.8 MeV  

E-Print Network [OSTI]

Benchmarking of evaluated nuclear data libraries was performed for $\\sim 14.8$ MeV neutrons on Gallium targets. The experiments were performed at China Institute of Atomic Energy(CIAE). Solid samples of natural Gallium (3.2 cm and 6.4 cm thick) were bombarded by $\\sim 14.8$ MeV neutrons and leakage neutron energy spectra were measured at 60$^{\\circ}$ and 120$^{\\circ}$. The measured spectra are rather well reproduced by MCNP-4C simulations with the CENDL-3.1, ENDF/B-VII and JENDL-4.0 evaluated nuclear data libraries, except for the inelastic contributions around $E_{n} = 10-13$ MeV. All three libraries significantly underestimate the inelastic contributions. The inelastic contributions are further studied, using the Talys simulation code and the experimental spectra are reproduced reasonably well in the whole energy range by the Talys calculation, including the inelastic contributions.

R. Han; R. Wada; Z. Chen; Y. Nie; X. Liu; S. Zhang; P. Ren; B. Jia; G. Tian; F. Luo; W. Lin; J. Liu; F. Shi; M. Huang; X. Ruan; J. Ren; Z. Zhou; H. Huang; J. Bao; K. Zhang; B. Hu

2014-11-03T23:59:59.000Z

266

Thermodynamic property evaluation and magnetic refrigeration cycle analysis for gadolinium gallium garnet  

SciTech Connect (OSTI)

Based on relevant material property data and previous model formulations, a magnetothermodynamic property map for gadolinium gallium garnet (Gd{sub 3}Ga{sub 5}O{sub 12}) was adapted for refrigeration cycle analysis in the temperature range 4-40 K and the magnetic field range 0-6 T. Employing methods similar to those previously developed for other materials and temperature ranges, assessments of limitations and relative performance were made for Carnot, ideal regenerative, and pseudo-constant field regenerative cycles. It was found that although Carnot cycle limitations on available temperature lift for gadolinium gallium garnet are not as severe as the limitations for materials previously examined, considerable improvement in cooling capacity and temperature lift combinations can be achieved by using regenerative cycles if serious loss mechanisms are avoided.

Murphy, R.W.

1994-12-01T23:59:59.000Z

267

K.K. Gan Joint SLHC Opto Working Group 1 Results of Opto-Link R&D  

E-Print Network [OSTI]

Joint SLHC Opto Working Group 11 K.K. Gan 11 VCSEL Power vs Dosage AOC (5 & 10 Gb/s) survive to SLHC instead of 5,000 fb-1 PIN: Si: TrueLight, Hamamatsu GaAs: AOC, ULM, Optowell VCSEL: AOC, Optowell, ULM? August 08 with 24 GeV/c p (CERN) #12;K.K. Gan Joint SLHC Opto Working Group

Gan, K. K.

268

PHYSICAL REVIEW B 86, 075207 (2012) Optical signature of Mg-doped GaN: Transfer processes  

E-Print Network [OSTI]

results in the task of bipolar doping of intermediate and wide band-gap materials like CdS,1Ā­3 ZnSe,4 ZnPHYSICAL REVIEW B 86, 075207 (2012) Optical signature of Mg-doped GaN: Transfer processes G; published 23 August 2012) Mg doping of high quality, metal organic chemical vapor deposition grown GaN films

Nabben, Reinhard

269

Influence of growth temperature and temperature ramps on deep level defect incorporation in m-plane GaN  

SciTech Connect (OSTI)

The dependence of deep level defect incorporation in m-plane GaN films grown by metal-organic chemical vapor deposition on bulk m-plane GaN substrates as a function of growth temperature (T{sub g}) and T{sub g} ramping method was investigated using deep level optical spectroscopy. Understanding the influence of T{sub g} on GaN deep level incorporation is important for InGaN/GaN multi-quantum well (MQW) light emitting diodes (LEDs) and laser diodes (LDs) because GaN quantum barrier (QB) layers are grown much colder than thin film GaN to accommodate InGaN QW growth. Deep level spectra of low T{sub g} (800?°C) GaN films grown under QB conditions were compared to deep level spectra of high T{sub g} (1150?°C) GaN. Reducing T{sub g}, increased the defect density significantly (>50×) through introduction of emergent deep level defects at 2.09?eV and 2.9?eV below the conduction band minimum. However, optimizing growth conditions during the temperature ramp when transitioning from high to low T{sub g} substantially reduced the density of these emergent deep levels by approximately 40%. The results suggest that it is important to consider the potential for non-radiative recombination in QBs of LED or LD active regions, and tailoring the transition from high T{sub g} GaN growth to active layer growth can mitigate such non-radiative channels.

Armstrong, A. M., E-mail: aarmstr@sandia.gov [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Kelchner, K. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States)] [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States); Nakamura, S.; DenBaars, S. P. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States) [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States); Materials Department, University of California, Santa Barbara, California 93106 (United States); Speck, J. S. [Materials Department, University of California, Santa Barbara, California 93106 (United States)] [Materials Department, University of California, Santa Barbara, California 93106 (United States)

2013-12-02T23:59:59.000Z

270

Growth and characterizations of GaN micro-rods on graphene films for flexible light emitting diodes  

SciTech Connect (OSTI)

We report the growth of GaN micro-rods and coaxial quantum-well heterostructures on graphene films, together with structural and optical characterization, for applications in flexible optical devices. Graphene films were grown on Cu foil by means of chemical vapor deposition, and used as the substrates for the growth of the GaN micro-rods, which were subsequently transferred onto SiO{sub 2}/Si substrates. Highly Si-doped, n-type GaN micro-rods were grown on the graphene films using metal–organic chemical vapor deposition. The growth and vertical alignment of the GaN micro-rods, which is a critical factor for the fabrication of high-performance light-emitting diodes (LEDs), were characterized using electron microscopy and X-ray diffraction. The GaN micro-rods exhibited promising photoluminescence characteristics for optoelectronic device applications, including room-temperature stimulated emission. To fabricate flexible LEDs, In{sub x}Ga{sub 1–x}N/GaN multiple quantum wells and a p-type GaN layer were deposited coaxially on the GaN micro-rods, and transferred onto Ag-coated polymer substrates using lift-off. Ti/Au and Ni/Au metal layers were formed to provide electrical contacts to the n-type and p-type GaN regions, respectively. The micro-rod LEDs exhibited intense emission of visible light, even after transfer onto the flexible polymer substrate, and reliable operation was achieved following numerous cycles of mechanical deformation.

Chung, Kunook; Beak, Hyeonjun; Tchoe, Youngbin; Oh, Hongseok; Yi, Gyu-Chul, E-mail: gcyi@snu.ac.kr [Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 151-747 (Korea, Republic of); Yoo, Hyobin; Kim, Miyoung [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

2014-09-01T23:59:59.000Z

271

Continuous Fiber Ceramic Composite (CFCC) Program: Gaseous Nitridation  

SciTech Connect (OSTI)

Textron has developed a mature process for the fabrication of continuous fiber ceramic composite (CFCC) tubes for application in the aluminum processing and casting industry. The major milestones in this project are System Composition; Matrix Formulation; Preform Fabrication; Nitridation; Material Characterization; Component Evaluation

R. Suplinskas G. DiBona; W. Grant

2001-10-29T23:59:59.000Z

272

BORON NITRIDE CAPACITORS FOR ADVANCED POWER ELECTRONIC DEVICES  

SciTech Connect (OSTI)

This project fabricates long-life boron nitride/boron oxynitride thin film -based capacitors for advanced SiC power electronics with a broad operating temperature range using a physical vapor deposition (PVD) technique. The use of vapor deposition provides for precise control and quality material formation.

N. Badi; D. Starikov; C. Boney; A. Bensaoula; D. Johnstone

2010-11-01T23:59:59.000Z

273

Novel compound semiconductor devices based on III-V nitrides  

SciTech Connect (OSTI)

New developments in dry and wet etching, ohmic contacts and epitaxial growth of Ill-V nitrides are reported. These make possible devices such as microdisk laser structures and GaAs/AlGaAs heterojunction bipolar transistors with improved InN ohmic contacts.

Pearton, S.J.; Abernathy, C.R. [Florida Univ., Gainesville, FL (United States); Ren, F. [AT & T Bell Laboratories, Murray Hill, NJ (United States)] [and others

1995-10-01T23:59:59.000Z

274

Nitridation of zirconium using energetic ions from plasma focus device  

Science Journals Connector (OSTI)

The nitridation of zirconium disks is achieved by irradiating energetic nitrogen ions from 2.3 kJ plasma focus device using multiple focus deposition shots (10, 20, 30 and 40) at different angular positions with respect to the anode axis. The X-ray diffraction analysis reveals the evolution of ZrN, Zr2N and Zr3N4 phases of zirconium nitride depending upon the ion energy flux and angular positions. The crystallite size of ZrN and Zr2N phases increases by increasing the number of focus deposition shots. The residual stresses estimated for Zr (101), ZrN (111) and ZrN (200) phases are maximum in the nitrided surfaces at lower nitrogen ion dose, decreases as the nitrogen ion dose increases. The field emission scanning electron microscopy results exhibit the uniform and smooth film of zirconium nitride with granular surface morphology at 10° angular position. The energy dispersive X-rays spectroscopy data indicate that nitrogen content in the film is improved for higher nitrogen ion dose while reduced at larger angular positions. The Vickers microhardness of the film is enhanced up to 400%. The microhardness increases by increasing the nitrogen ion dose and decreases rapidly by increasing the angular position.

I.A. Khan; M. Hassan; R. Ahmad; A. Qayyum; G. Murtaza; M. Zakaullah; R.S. Rawat

2008-01-01T23:59:59.000Z

275

Design and Simulation of Novel Enhancement Mode 5–20 kV GaN Vertical Superjunction High Electron Mobility Transistors for Smart Grid Applications  

Science Journals Connector (OSTI)

We report on the design, simulations and optimization of a novel enhancement mode 5–20 kV GaN vertical superjunction (SJ) high electron mobility transistor (HEMT). We optimize the space charge in GaN pillars using GaN SJ p–n diode for the best trade-off between breakdown voltage (BV) and specific on-resistance (Ronsp), by varying the pillar dosage, length and width. The resulting GaN SJ field effect transistor (FET) structure is projected to have, for example, Ronsp of 4.2 m? cm2 with BV of 12.4 kV.

Zhongda Li; T. Paul Chow

2013-01-01T23:59:59.000Z

276

Subpicosecond time-resolved Raman studies of nonequilibrium excitations in wurtzite GaN  

SciTech Connect (OSTI)

Non-equilibrium electron distributions as well as phonon dynamics in wurtzite GaN have been measured by subpicosecond time-resolved Raman spectroscopy. The experimental results have demonstrated that for electron densities n {ge} 5 {times} 10{sup 17} cm{sup {minus}3}, the non-equilibrium electron distributions in wurtzite GaN can be very well described by Fermi-Dirac distribution functions with the temperature of electrons substantially higher than that of the lattice. The population relaxation time of longitudinal optical phonons was directly measured to be {tau} {approx_equal} 5 {+-} 1 ps at T = 25 K. The experimental results on the temperature dependence of the lifetime of longitudinal optical phonons suggest that the primary decay channels for these phonons are the decay into (1) one transverse optical phonon and one high energy, longitudinal or transverse acoustical phonons; and (2) one transverse optical phonon and one E{sub 2} phonon.

Tsen, K.T.; Ferry, D.K. [Arizona State Univ., Tempe, AZ (United States). Dept. of Physics and Astronomy; Joshi, R.P. [Old Dominion Univ., Norfolk, VA (United States). Dept. of Electrical Engineering; Botchkarev, A.; Sverdlov, B.; Salvador, A.; Morkoc, H. [Univ. of Illinois, Urbana, IL (United States). Coordinated Science Lab.

1997-12-31T23:59:59.000Z

277

K.K. Gan ATLAS Pixel Week 1 New Results on Opto-Electronics  

E-Print Network [OSTI]

with lower thresholds with BPM/DRX ] opto-board design is compatible with BPM/DRX PIN Current Thresholds with BPM/DRX 0 5 10 15 20 25 30 35 link#1 link#2 link#3 link#4 link#5 link#6 link#7 Ipin(mA) Opto-Board on Test Board Opto-Board on Test Board with BPM/DRX #12;K.K. Gan ATLAS Pixel Week 8 l one irradiated VCSEL

Gan, K. K.

278

Sandia National Laboratories: Energy Efficiency  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Single-mode gallium nitride nanowire lasers On January 28, 2013, in EC, Energy Efficiency, Solid-State Lighting A new top-down method for fabricating gallium nitride...

279

Sandia National Laboratories: BES Web Highlight: Single-mode...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ClimateECEnergyEnergy EfficiencyBES Web Highlight: Single-mode gallium nitride nanowire lasers BES Web Highlight: Single-mode gallium nitride nanowire lasers "Solid-state Lighting:...

280

Theoretical and experimental study of dynamics of photoexcited carriers in GaN  

SciTech Connect (OSTI)

We present a theoretical and experimental study of the sub-picosecond dynamics of photo-excited carriers in GaN. In the theoretical model, interaction with an external ultrafast laser pulse is treated coherently and to account for the scattering mechanisms and dephasing processes, a generalized Monte-Carlo simulation is used. The scattering mechanisms included are carrier interactions with polar optical phonons and acoustic phonons, and carrier-carrier Coulomb interactions. We study the effect of different scattering mechanisms on the carrier densities. In the case that the excitation energy satisfies the threshold for polar optical scattering, phonon contribution is the dominant process in relaxing the system, otherwise, carrier-carrier mechanism is dominant. Furthermore, we present the temperature and pulse power dependent normalized luminescence intensity. The results are presented over a range of temperatures, electric field, and excitation energy of the laser pulse. For comparison, we also report the experimental time-resolved photoluminescence studies on GaN samples. There is a good agreement between the simulation and experiment in normalized luminescence intensity results. Therefore, we show that we can explain the dynamics of the photo-excited carriers in GaN by including only carrier-carrier and carrier-phonon interactions and a relatively simple two-band electronic structure model.

Shishehchi, Sara; Bellotti, Enrico, E-mail: bellotti@bu.edu [ECE Department, Boston University, 8 Saint Mary's Street, Boston, Massachusetts 02215 (United States); Rudin, Sergey; Garrett, Gregory A.; Wraback, Michael [Sensors and Electron Devices Directorate, US Army Research Laboratory, 2800 Powder Mill Rd, Adelphi, Maryland 20783 (United States)

2013-12-21T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Anisotropy of effective electron masses in highly doped nonpolar GaN  

SciTech Connect (OSTI)

The anisotropic effective electron masses in wurtzite GaN are determined by generalized infrared spectroscopic ellipsometry. Nonpolar (112{sup Æ}0) oriented thin films allow accessing both effective masses, m{sub ?}{sup *} and m{sub ?}{sup *}, by determining the screened plasma frequencies. A n-type doping range up to 1.7?×?10{sup 20}?cm{sup ?3} is investigated. The effective mass ratio m{sub ?}{sup *}/m{sub ?}{sup *} is obtained with highest accuracy and is found to be 1.11 independent on electron concentration up to 1.2?×?10{sup 20}?cm{sup ?3}. For higher electron concentrations, the conduction band non-parabolicity is mirrored in changes. Absolute values for effective electron masses depend on additional input of carrier concentrations determined by Hall effect measurements. We obtain m{sub ?}{sup *}=(0.239±0.004)m{sub 0} and m{sub ?}{sup *}=(0.216±0.003)m{sub 0} for the parabolic range of the GaN conduction band. Our data are indication of a parabolic GaN conduction band up to an energy of approximately 400?meV above the conduction band minimum.

Feneberg, Martin, E-mail: martin.feneberg@ovgu.de; Lange, Karsten; Lidig, Christian; Wieneke, Matthias; Witte, Hartmut; Bläsing, Jürgen; Dadgar, Armin; Krost, Alois; Goldhahn, Rüdiger [Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg (Germany)] [Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg (Germany)

2013-12-02T23:59:59.000Z

282

Red light emitting solid state hybrid quantum dot–near-UV GaN LED devices  

Science Journals Connector (OSTI)

We produced core–shell (CdSe)ZnSe quantum dots by direct colloidal chemical synthesis and the surface-passivation method—an overcoating of the core CdSe with a larger-bandgap material ZnSe. The (CdSe)ZnSe quantum dots(QDs) play the role of a colour conversion centre. We call these quantum dots nanophosphors. We fabricated red light emitting hybrid devices of (CdSe)ZnSe QDs and a near-UV GaN LED by combining red light emitting (CdSe)ZnSe quantum dots (as a colour conversion centre) with a near-UV(NUV) GaN LED chip (as an excitation source). A few good red phosphors have been known for UV excitation wavelengths, and red phosphors for UV excitation have been sought for a long time. Here we tested the possibility of using (CdSe)ZnSe QDs as red nanophosphors for UV excitation. The fabricated red light emitting hybrid device of (CdSe)ZnSe and a NUV GaN LED chip showed a good luminance. We demonstrated that the (CdSe)ZnSe quantum dots were promising red nanophosphors for NUV excitation and that a red LED made of QDs and a NUV excitation source was a highly efficient hybrid device.

Hongjoo Song; Seonghoon Lee

2007-01-01T23:59:59.000Z

283

E-Print Network 3.0 - alkali-resistant silicon nitride Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Computer Science Collection: Engineering ; Materials Science 4 Published in 'Silicon Carbide, III-Nitrides and Related Materials', Year: 1998, pp: 1149-1152 Periodical: Materials...

284

David Niedzwiecki 3/2/2012 2:37:42 PM Protocol for Ultrathin Nitride Membranes  

E-Print Network [OSTI]

necessary to remove the nitride layer. -Use the CHF3/CF4/Ar oxide removal protocol to remove the oxide. Do 8

Movileanu, Liviu

285

Method and apparatus for use of III-nitride wide bandgap semiconductors in optical communications  

DOE Patents [OSTI]

The present disclosure relates to the use of III-nitride wide bandgap semiconductor materials for optical communications. In one embodiment, an optical device includes an optical waveguide device fabricated using a III-nitride semiconductor material. The III-nitride semiconductor material provides for an electrically controllable refractive index. The optical waveguide device provides for high speed optical communications in an infrared wavelength region. In one embodiment, an optical amplifier is provided using optical coatings at the facet ends of a waveguide formed of erbium-doped III-nitride semiconductor materials.

Hui, Rongqing (Lenexa, KS); Jiang,Hong-Xing (Manhattan, KS); Lin, Jing-Yu (Manhattan, KS)

2008-03-18T23:59:59.000Z

286

E-Print Network 3.0 - aluminum nitride ceramics Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Emily Parker, Vanni Lughi, Noel C. MacDonald Summary: , biocompatibility, and high fracture toughness. As a piezoelectric ceramic, aluminum nitride is compatible... Aluminum...

287

Metal clusters with exposed and low-coordinate nitride nitrogen atoms  

SciTech Connect (OSTI)

The synthesis and structural characterization of a prototypic series of iron nitride clusters in which the nitrogen atoms are exposed and of low coordination number, namely four and five are described. The term nitride denotes species in which a nitrogen atom is only within bonding distance of metal atoms. The clusters prepared were (Fe/sub 4/N(CO)/sub 12//sup -/), (Fe/sub 5/N(CO)/sub 14//sup -/). The 62-electron four-iron nitrides should have butterfly structures and the 74-electron five-iron nitrides should have square-pyramidal structures. 1 figure.

Tachikawa, M. (Univ. of California, Berkeley); Stein, J.; Muetterties, E.L.; Teller, R.G.; Beno, M.A.; Gebert, E.; Williams, J.M.

1980-10-08T23:59:59.000Z

288

Chemical preparation and shock wave compression of carbon nitride precursors  

SciTech Connect (OSTI)

Two synthetic routes have been developed to produce high-molecular-weight organic precursors containing a high weight fraction of nitrogen. One of the precursors is a pyrolysis residue of melamine-formaldehyde resin. The second precursor is the byproduct of an unusual low-temperature combustion reaction of tetrazole and its sodium salt. These precursors have been shock compressed under typical conditions for diamond and wurtzite boron nitride synthesis in an attempt to recover a new ultrahard carbon nitride. The recovered material has been analyzed by X-ray diffraction, FTIR, and Raman microprobe analysis. Diamond is present in the recovered material. This diamond is well ordered relative to diamond shock synthesized from carbonaceous starting materials.

Wixon, M.R. (KMS Fusion, Inc., Ann Arbor, MI (USA))

1990-07-01T23:59:59.000Z

289

Electrically dependent bandgaps in graphene on hexagonal boron nitride  

SciTech Connect (OSTI)

We present first-principles calculations on the bandgap of graphene on a layer of hexagonal boron nitride in three different stacking configurations. Relative stability of the configurations is identified and bandgap tunability is demonstrated through the application of an external, perpendicularly applied electric field. We carefully examine the bandgap's sensitivity to both magnitude of the applied field as well as separation between the graphene and hexagonal boron nitride layers. Features of the band structure are examined and configuration-dependent relationships between the field and bandgap are revealed and elucidated through the atom-projected density of states. These findings suggest the potential for opening and modulating a bandgap in graphene as high as several hundred meV.

Kaplan, D., E-mail: daniel.b.kaplan.civ@mail.mil; Swaminathan, V. [U.S. Army RDECOM-ARDEC, Fuze Precision Armaments and Technology Directorate, Picatinny Arsenal, New Jersey 07806 (United States); Recine, G. [Department of Applied Physics, Polytechnic Institute of New York University, Brooklyn, New York 11201 (United States); Department of Physics and Engineering Physics, Fordham University, Bronx, New York 10458 (United States)

2014-03-31T23:59:59.000Z

290

Study of nitrogen-rich titanium and zirconium nitride films  

SciTech Connect (OSTI)

Thin titanium nitride (TiN) and zirconium nitride (ZrN) films containing excess nitrogen up to 59 and 63 at. % N, respectively, were deposited on austenitic stainless-steel substrates by reactive triode ion plating at about 823 K. The film structure and surface chemistry were studied using x-ray diffraction, scanning Auger spectroscopy, and electron energy-loss spectroscopy (EELS). In TiN films only the face-centered-cubic mononitride phase was detected. The lattice parameter of the stoichiometric TiN film was larger than the corresponding bulk value and it increased with increasing nitrogen content. The lattice parameter of overstoichiometric ZrN films showed abnormal behavior when calculated from different diffracting planes. This behavior together with the EELS and other measurements indicate that a dielectric Zr/sub 3/N/sub 4/ phase was formed at overstoichiometric compositions.

Ristolainen, E.O.; Molarius, J.M.; Korhonen, A.S.; Lindroos, V.K.

1987-07-01T23:59:59.000Z

291
292

314 IEEE MICROWAVE AND GUIDED WAVE LETTERS, VOL. 9, NO. 8, AUGUST 1999 39-GHz GaN-Based Microwave Power  

E-Print Network [OSTI]

As-based counterparts of the same sizes. Index Terms--Amplifier, field-effect transistors, gallium-nitride (Ga

York, Robert A.

293

3-D view of 1-D nanostructures January 6th, 2012 Filed under Nano Science Tagged cormick-school, engineering,  

E-Print Network [OSTI]

cormick-school, engineering, esearchers-at-the, gallium-nitride, great-promise, have-found, mccormick

Espinosa, Horacio D.

294

15 - Processing of Refractory Carbides and Nitrides (Coatings)  

Science Journals Connector (OSTI)

Publisher Summary This chapter reviews the coating processes of refractory carbides and nitrides. Coatings of refractory carbides and nitrides have great industrial importance with a wide range of applications in semiconductors and other electronic components, in cutting tools, gas-turbine vanes and blades, precision bearings, punch sets, extruders, prostheses, and many other products. The surface of a material may be exposed to wear, corrosion, radiation, electrical or magnetic fields, and other phenomena and hence, it must have the ability to withstand these environments. This can be accomplished by coating the base material to obtain a composite in which the surface properties may be considerably different from those of the substrate. Chemical vapor deposition (CVD) and physical vapor deposition (PVD) belong to the class of vapor-transfer processes, which are atomistic in nature—that is, the deposition species are atoms or molecules or a combination of these. The coatings are also commonly known as thin-films when their thickness is less than 10 ?m. CVD is a versatile process that is well adapted to the production of all the refractory carbides and nitrides, not only as coatings but also as powders, bulk/monolithic components, and fibers. It may be defined as the deposition of a solid on a heated surface from a chemical reaction in the vapor phase.

Hugh O. Pierson

1996-01-01T23:59:59.000Z

295

Dual operation characteristics of resistance random access memory in indium-gallium-zinc-oxide thin film transistors  

SciTech Connect (OSTI)

In this study, indium-gallium-zinc-oxide thin film transistors can be operated either as transistors or resistance random access memory devices. Before the forming process, current-voltage curve transfer characteristics are observed, and resistance switching characteristics are measured after a forming process. These resistance switching characteristics exhibit two behaviors, and are dominated by different mechanisms. The mode 1 resistance switching behavior is due to oxygen vacancies, while mode 2 is dominated by the formation of an oxygen-rich layer. Furthermore, an easy approach is proposed to reduce power consumption when using these resistance random access memory devices with the amorphous indium-gallium-zinc-oxide thin film transistor.

Yang, Jyun-Bao; Chen, Yu-Ting; Chu, Ann-Kuo [Department of Photonics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Chang, Ting-Chang, E-mail: tcchang@mail.phys.nsysu.edu.tw [Department of Photonics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Advanced Optoelectronics Technology Center, National Cheng Kung University, Taiwan (China); Huang, Jheng-Jie; Chen, Yu-Chun; Tseng, Hsueh-Chih [Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Sze, Simon M. [Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Department of Electronics Engineering, National Chiao Tung University, Hsinchu, Taiwan (China)

2014-04-14T23:59:59.000Z

296

Power Electronics Reliability Kick Off Meeting Ā… Silicon Power Corp. & Sandia Labs  

Broader source: Energy.gov (indexed) [DOE]

Reliability Reliability 2010 Update Conference - DOE ESS Program November 4, 2010 Mark A. Smith - Systems Readiness & Sustainment Technologies Robert Kaplar, Matthew Marinella, Reinhard Brock, James Stanley, and Michael King - Radiation Hard CMOS Technology Stan Atcitty - Energy Infrastructure and Distributed Energy Resources Sandia National Laboratories Thanks to Dr. Imre Gyuk for supporting this work. Project Goals * Use experiments and modeling to investigate and characterize stress-related failure modes of post-silicon power electronic (PE) devices such as silicon carbide (SiC) and gallium nitride (GaN) switches. * Seek opportunities for condition monitoring (CM) and prognostics and health management (PHM) to further enhance the reliability of power electronics devices and equipment.

297

Synthesis of graphene nanoribbons from amyloid templates by gallium vapor-assisted solid-phase graphitization  

SciTech Connect (OSTI)

Single- and double-layer graphene nanoribbons (GNRs) with widths of around 10?nm were synthesized directly onto an insulating substrate by solid-phase graphitization using a gallium vapor catalyst and carbon templates made of amyloid fibrils. Subsequent investigation revealed that the crystallinity, conductivity, and carrier mobility were all improved by increasing the temperature of synthesis. The carrier mobility of the GNR synthesized at 1050?°C was 0.83 cm{sup 2}/V?s, which is lower than that of mechanically exfoliated graphene. This is considered to be most likely due to electron scattering by the defects and edges of the GNRs.

Murakami, Katsuhisa, E-mail: k.murakami@bk.tsukuba.ac.jp; Dong, Tianchen; Kajiwara, Yuya; Takahashi, Teppei; Fujita, Jun-ichi [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Tsukuba Research Center for Interdisciplinary Materials Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Hiyama, Takaki; Takai, Eisuke; Ohashi, Gai; Shiraki, Kentaro [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan)

2014-06-16T23:59:59.000Z

298

Scanning tunneling microscopy on unpinned GaN(11Æ00) surfaces: Invisibility of valence-band states  

Science Journals Connector (OSTI)

We investigated the origins of the tunnel current in scanning tunneling microscopy (STM) and spectroscopy experiments on GaN(11Æ00) surfaces. By calculating the tunnel currents in the presence of a tip-induced band bending for unpinned n-type GaN(11Æ00) surfaces, we demonstrate that only conduction-band states are observed at positive and negative voltage polarities independent of the doping concentration. Valence-band states remain undetectable because tunneling out of the electron-accumulation zone in conduction-band states dominates by four orders of magnitude. As a result band-gap sizes cannot be determined by STM on unpinned GaN(11Æ00) surfaces. Appropriate band-edge positions and gap sizes can be determined on pinned surfaces.

Ph. Ebert, L. Ivanova, and H. Eisele

2009-08-24T23:59:59.000Z

299

Ab initio study on noncompensated CrO codoping of GaN for enhanced solar energy conversion  

SciTech Connect (OSTI)

We describe a novel photocatalyst obtained by codoping GaN with CrO, according to a new "noncompensated" codoping concept based on first-principles calculations. The approach enables controllable narrowing of the GaN band gap with significantly enhanced carrier mobility and photocatalytic activity in the visible light region and thus offers immense potential for application in solar energy conversion, water splitting, and a variety of solar-assisted photocatalysis. Our calculations indicate that the formation energy for the cation doping is greatly reduced by noncompensated codoping with an anion. Although Cr doping alone can split the band gap with the formation of an intermediate band, the mobility is low due to carrier trapping by the localized states. The first-principles calculations also demonstrate that CrO codoping of GaN shifts the Fermi level into the conduction band resulting in high carrier density and mobility.

Pan, Hui [ORNL; Gu, Baohua [ORNL; Eres, Gyula [ORNL; Zhang, Zhenyu [ORNL

2010-03-01T23:59:59.000Z

300

Development of a Bulk GaN Growth Technique for Low Defect Density, Large-Area Native Substrates  

Broader source: Energy.gov (indexed) [DOE]

the Electrochemical Solution the Electrochemical Solution Growth (ESG) Technique for Native GaN Substrates DOE Energy Storage & Power Electronics Research Program 30 September 2008 PI: Karen Waldrip Advanced Power Sources R&D, Dept 2546 PM: Stan Atcitty, John Boyes Sandia National Laboratories, Albuquerque, NM, 87185 Sponsor: Gil Bindewald, DOE Power Electronics & Energy Storage Program Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Outline * Motivation * Existing GaN Growth Technique - Epitaxial Lateral Overgrowth - Methods for Growing Bulk GaN * Development of the Electrochemical Solution Growth Technique

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Excitons in Boron Nitride Nanotubes: Dimensionality Effects Ludger Wirtz,1,2  

E-Print Network [OSTI]

Excitons in Boron Nitride Nanotubes: Dimensionality Effects Ludger Wirtz,1,2 Andrea Marini,3; published 30 March 2006) We show that the optical absorption spectra of boron nitride (BN) nanotubes are dominated by strongly bound excitons. Our first-principles calculations indicate that the binding energy

Marini, Andrea

302

Ultra-thin ohmic contacts for p-type nitride light emitting devices  

DOE Patents [OSTI]

A semiconductor based Light Emitting Device (LED) can include a p-type nitride layer and a metal ohmic contact, on the p-type nitride layer. The metal ohmic contact can have an average thickness of less than about 25 .ANG. and a specific contact resistivity less than about 10.sup.-3 ohm-cm.sup.2.

Raffetto, Mark (Raleigh, NC); Bharathan, Jayesh (Cary, NC); Haberern, Kevin (Cary, NC); Bergmann, Michael (Chapel Hill, NC); Emerson, David (Chapel Hill, NC); Ibbetson, James (Santa Barbara, CA); Li, Ting (Ventura, CA)

2012-01-03T23:59:59.000Z

303

Tunneling characteristics in chemical vapor deposited graphene hexagonal boron nitride graphene junctions  

E-Print Network [OSTI]

1 Tunneling characteristics in chemical vapor deposited graphene Ā­ hexagonal boron nitride Ā­ graphene junctions T. Roy1 , L. Liu2 , S. de la Barrera,3 B. Chakrabarti1,4 , Z. R. Hesabi1 , C. A. Joiner1 Abstract: Large area chemical vapor deposited graphene and hexagonal boron nitride was used to fabricate

Feenstra, Randall

304

One step process for producing dense aluminum nitride and composites thereof  

DOE Patents [OSTI]

A one step combustion process for the synthesis of dense aluminum nitride compositions is disclosed. The process comprises igniting pure aluminum powder in a nitrogen atmosphere at a pressure of about 1000 atmospheres or higher. The process enables the production of aluminum nitride bodies to be formed directly in a mold of any desired shape.

Holt, J. Birch (San Jose, CA); Kingman, Donald D. (Danville, CA); Bianchini, Gregory M. (Livermore, CA)

1989-01-01T23:59:59.000Z

305

carbides. The multiphase/polytypic region can be expected to occur also in the nitrides because  

E-Print Network [OSTI]

in valence electron concentration where sev- eral phases of the 3d, 4d, and 5d transition metal carbides have, Transition Metal Carbides and Nitrides (Academic Press, New York, 1971). 6. C. Maerky, M.-O. Guillou, J. L is predicted to be substantially enhanced over that of traditional transition metal car- bide/nitride coatings

Shen, Guoyin

306

Single-Crystalline Mesoporous Molybdenum Nitride Nanowires with Improved Electrochemical Properties  

E-Print Network [OSTI]

process. I. Introduction TRANSITION -metal oxides, carbides, sulfides, and nitrides are extensively, and catalytic properties.1Ā­4 Among the transition-metal com- pounds, transition-metal nitrides are regarded using transition-metal complex materials.16 However, the transi- tion-metal complex materials are lower

Cao, Guozhong

307

Hard superconducting nitrides Xiao-Jia Chen*, Viktor V. Struzhkin*, Zhigang Wu*, Maddury Somayazulu  

E-Print Network [OSTI]

(4). The refractory characteristics of these transition- metal nitrides and carbides have been, and hardness of selected superconducting transition-metal nitrides reveals inter- esting correlations among transition temperature (Tc) near 4 K when doped with boron (3). However, the transition-metal compounds

Wu, Zhigang

308

Large-scale well aligned carbon nitride nanotube films: Low temperature growth and electron field emission  

E-Print Network [OSTI]

Large-scale well aligned carbon nitride nanotube films: Low temperature growth and electron field emission Dingyong Zhong, Shuang Liu, Guangyu Zhang, and E. G. Wanga) State Key Laboratory for Surface Received 2 January 2001; accepted for publication 13 March 2001 Large-scale well aligned carbon nitride

Zhang, Guangyu

309

US Department of Energy (DOE)/Gosatomnadzor (GAN) of Russia project at the Petersburg Nuclear Physics Institute (PNPI)  

SciTech Connect (OSTI)

This paper presents a summary of work accomplished within the scope of the DOE-Gosatomnadzor (GAN) Agreement to reduce vulnerability to theft of direct-use nuclear materials in Russia. The DOE-GAN agreement concerns the Russian Academy of Science B.P. Konstantinov Petersburg Nuclear Physics Institute (PNPI), located 45 kilometers from St. Petersburg. The PNPI operates facilities to research basic nuclear physics. Current world conditions require particular attention to the issue of Material Protection, Control, and Accounting (MPC&A) of nuclear materials. The long-term plan to increase security at the facility is outlined, including training, physical protection upgrades, and material control and accountability. 4 figs.

Baranov, I.A.; Konoplev, K.A. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Hauser, G.C. [Sandia National Lab., Albuquerque, NM (United States)] [and others

1997-08-01T23:59:59.000Z

310

The impact of nanoperforation on persistent photoconductivity and optical quenching effects in suspended GaN nanomembranes  

SciTech Connect (OSTI)

We report on fabrication of suspended ?15?nm thick GaN membranes nanoperforated in an ordered fashion using direct writing of negative charges by focused ion beam and subsequent photoelectrochemical etching of GaN epilayers. Both continuous and nanoperforated membranes exhibit persistent photoconductivity (PPC), which can be optically quenched under excitation by 546?nm radiation. Optical quenching of PPC occurs also under relatively intense intrinsic excitation of nanoperforated membranes by 355?nm radiation at T?

Volciuc, Olesea, E-mail: olesea.volciuc@gmail.com [Institute of Solid State Physics, University of Bremen, Bremen 28334 (Germany) [Institute of Solid State Physics, University of Bremen, Bremen 28334 (Germany); National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova, Republic of); Braniste, Tudor [National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova, Republic of)] [National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova, Republic of); Tiginyanu, Ion, E-mail: tiginyanu@asm.md [National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova, Republic of) [National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova, Republic of); Institute of Electronic Engineering and Nanotechnologies, Academy of Sciences of Moldova, Chisinau 2028 (Moldova, Republic of); Stevens-Kalceff, Marion A. [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia)] [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia); Ebeling, Jakob; Aschenbrenner, Timo; Hommel, Detlef; Gutowski, Jürgen [Institute of Solid State Physics, University of Bremen, Bremen 28334 (Germany)] [Institute of Solid State Physics, University of Bremen, Bremen 28334 (Germany); Ursaki, Veaceslav [Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau 2028 (Moldova, Republic of)] [Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau 2028 (Moldova, Republic of)

2013-12-09T23:59:59.000Z

311

Characterization of gallium-doped CdS thin films grown by chemical bath Hani Khallaf a  

E-Print Network [OSTI]

Characterization of gallium-doped CdS thin films grown by chemical bath deposition Hani Khallaf In-situ doping with group III elements has been widely used to decrease the dark resistivity of CdS technique for aluminum in-situ doping of CdS. We have also shown that due to extremely low solubility

Chow, Lee

312

Synthesis of Gallium Oxide Hydroxide Crystals in Aqueous Solutions with or without Urea and Their Calcination Behavior  

E-Print Network [OSTI]

solution of gallium(III) nitrate and stirring at 90Ā°C for 10 h, followed by calcination of the recovered of solid electro- lytes of superior (as compared with Y-stabilized zirconia) ionic conductivity, i.e., La0-chemical synthesis of powders of doped LaGaO3 fuel cell ceramics.24,25 The first experimental study

Tas, A. Cuneyt

313

An assessment of the validity of cerium oxide as a surrogate for plutonium oxide gallium removal studies  

SciTech Connect (OSTI)

Methods for purifying plutonium metal have long been established. These methods use acid solutions to dissolve and concentrate the metal. However, these methods can produce significant mixed waste, that is, waste containing both radioactive and chemical hazards. The volume of waste produced from the aqueous purification of thousands of weapons would be expensive to treat and dispose. Therefore, a dry method of purification is highly desirable. Recently, a dry gallium removal research program commenced. Based on initial calculations, it appeared that a particular form of gallium (gallium suboxide, Ga{sub 2}O) could be evaporated from plutonium oxide in the presence of a reducing agent, such as small amounts of hydrogen dry gas within an inert environment. Initial tests using ceria-based material (as a surrogate for PuO{sub 2}) showed that thermally-induced gallium removal (TIGR) from small samples (on the order of one gram) was indeed viable. Because of the expense and difficulty of optimizing TIGR from plutonium dioxide, TIGR optimization tests using ceria have continued. This document details the relationship between the ceria surrogate tests and those conducted using plutonia.

Kolman, D.G.; Park, Y.; Stan, M.; Hanrahan, R.J. Jr.; Butt, D.P.

1999-03-01T23:59:59.000Z

314

Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride by metalorganic vapor-phase epitaxy  

E-Print Network [OSTI]

Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride to examine the effects of carbon tetrachloride concentration and temperature on the morphology of carbon with increasing carbon tetrachloride concentration. Step bunching and pinning was observed at a IV/III ratio

Li, Lian

315

Nanoscale size dependence parameters on lattice thermal conductivity of Wurtzite GaN nanowires  

SciTech Connect (OSTI)

Graphical abstract: Temperature dependence of calculated lattice thermal conductivity of Wurtzite GaN nanowires. Highlights: Black-Right-Pointing-Pointer A modified Callaway model is used to calculate lattice thermal conductivity of Wurtzite GaN nanowires. Black-Right-Pointing-Pointer A direct method is used to calculate phonon group velocity for these nanowires. Black-Right-Pointing-Pointer 3-Gruneisen parameter, surface roughness, and dislocations are successfully investigated. Black-Right-Pointing-Pointer Dislocation densities are decreases with the decrease of wires diameter. -- Abstract: A detailed calculation of lattice thermal conductivity of freestanding Wurtzite GaN nanowires with diameter ranging from 97 to 160 nm in the temperature range 2-300 K, was performed using a modified Callaway model. Both longitudinal and transverse modes are taken into account explicitly in the model. A method is used to calculate the Debye and phonon group velocities for different nanowire diameters from their related melting points. Effect of Gruneisen parameter, surface roughness, and dislocations as structure dependent parameters are successfully used to correlate the calculated values of lattice thermal conductivity to that of the experimentally measured curves. It was observed that Gruneisen parameter will decrease with decreasing nanowire diameters. Scattering of phonons is assumed to be by nanowire boundaries, imperfections, dislocations, electrons, and other phonons via both normal and Umklapp processes. Phonon confinement and size effects as well as the role of dislocation in limiting thermal conductivity are investigated. At high temperatures and for dislocation densities greater than 10{sup 14} m{sup -2} the lattice thermal conductivity would be limited by dislocation density, but for dislocation densities less than 10{sup 14} m{sup -2}, lattice thermal conductivity would be independent of that.

Mamand, S.M., E-mail: soran.mamand@univsul.net [Department of Physics, College of Science, University of Sulaimani, Sulaimanyah, Iraqi Kurdistan (Iraq); Omar, M.S. [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq)] [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq); Muhammad, A.J. [Department of Physics, College of Science, University of Kirkuk, Kirkuk (Iraq)] [Department of Physics, College of Science, University of Kirkuk, Kirkuk (Iraq)

2012-05-15T23:59:59.000Z

316

K.K. Gan TWEPP08 1 Results on Opto-Link R&D  

E-Print Network [OSTI]

-Hardness of GaAs PIN AOC ULM irradiate PIN with 24 GeV protons at CERN SLHC dosage: 2.6 x 1015 p/cm2 (8.2 x.25 0.50 0.13 AOC 2.5 0.60 0.19 Optowell 3.125 0.60 0.25 Hamamatsu G8921 2.5 0.50 0.32 Si Taiwan 1.0 0 channels 2008 irradiation with SLHC dosage: AOC(5 & 10 G) have good power #12;K.K. Gan TWEPP08 8

Gan, K. K.

317

K.K. Gan Siena08 1 Results on Opto-Link R&D  

E-Print Network [OSTI]

-Hardness of GaAs PIN AOC ULM irradiate PIN with 24 GeV protons at CERN SLHC dosage: 2.6 x 1015 p/cm2 (8.2 x.25 0.50 0.13 AOC 2.5 0.60 0.19 Optowell 3.125 0.60 0.25 Hamamatsu G8921 2.5 0.50 0.32 Si Taiwan 1.0 0 channels 2008 irradiation with SLHC dosage: AOC(5 & 10 G) have good power #12;K.K. Gan Siena08 9

Gan, K. K.

318

Boron nitride nanosheets as oxygen-atom corrosion protective coatings  

SciTech Connect (OSTI)

The research of two-dimensional nanomaterials for anticorrosion applications is just recently burgeoning. Herein, we demonstrate the boron nitride nanosheets (BNNSs) coatings for protecting polymer from oxygen-atom corrosion. High-quality BNNSs, which are produced by an effective fluid dynamics method with multiple exfoliation mechanisms, can be assembled into coatings with controlled thickness by vacuum filtration. After exposed in atom oxygen, the naked polymer is severely corroded with remarkable mass loss, while the BNNSs-coated polymer remains intact. Barrier and bonding effects of the BNNSs are responsible for the coating's protective performance. These preliminary yet reproducible results pave a way for resisting oxygen-atom corrosion.

Yi, Min [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Plasma Laboratory, Ministry-of-Education Key Laboratory of Fluid Mechanics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Shen, Zhigang, E-mail: shenzhg@buaa.edu.cn [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Plasma Laboratory, Ministry-of-Education Key Laboratory of Fluid Mechanics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); School of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Zhao, Xiaohu [Plasma Laboratory, Ministry-of-Education Key Laboratory of Fluid Mechanics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Liang, Shuaishuai [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Liu, Lei [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); School of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

2014-04-07T23:59:59.000Z

319

Excellent oxidation endurance of boron nitride nanotube field electron emitters  

SciTech Connect (OSTI)

Boron nitride nanotubes (BNNTs) are considered as a promising cold electron emission material owing to their negative electron affinity. BNNT field emitters show excellent oxidation endurance after high temperature thermal annealing of 600?°C in air ambient. There is no damage to the BNNTs after thermal annealing at a temperature of 600?°C and also no degradation of field emission properties. The thermally annealed BNNTs exhibit a high maximum emission current density of 8.39?mA/cm{sup 2} and show very robust emission stability. The BNNTs can be a promising emitter material for field emission devices under harsh oxygen environments.

Song, Yenan [Department of Micro/Nano Systems, Korea University, Seoul 136-713 (Korea, Republic of); Sun, Yuning; Hoon Shin, Dong; Nam Yun, Ki [School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Song, Yoon-Ho [Nano Electron-Source Creative Research Center, Creative and Challenging Research Division, ETRI, Daejeon 305-700 (Korea, Republic of); Milne, William I. [Electrical Engineering Division, Engineering Department, Cambridge University, Cambridge CB3 0FA (United Kingdom); Jin Lee, Cheol, E-mail: cjlee@korea.ac.kr [Department of Micro/Nano Systems, Korea University, Seoul 136-713 (Korea, Republic of); School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

2014-04-21T23:59:59.000Z

320

Method of nitriding niobium to form a superconducting surface  

DOE Patents [OSTI]

A method of forming a delta niobium nitride .delta.-NbN layer on the surface of a niobium object including cleaning the surface of the niobium object; providing a treatment chamber; placing the niobium object in the treatment chamber; evacuating the chamber; passing pure nitrogen into the treatment chamber; focusing a laser spot on the niobium object; delivering laser fluences at the laser spot until the surface of the niobium object reaches above its boiling temperature; and rastering the laser spot over the surface of the niobium object.

Kelley, Michael J.; Klopf, John Michael; Singaravelu, Senthilaraja

2014-08-19T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Field emission characteristics from graphene on hexagonal boron nitride  

SciTech Connect (OSTI)

An attempt has been made to utilize uniquely high electron mobility of graphene on hexagonal boron nitride (h-BN) to electron emitter. The field emission property of graphene/h-BN/Si structure has shown enhanced threshold voltage and emission current, both of which are key to develop novel vacuum nanoelectronics devices. The field emission property was discussed along with the electronic structure of graphene investigated by Fowler-Nordheim plot and ultraviolet photoelectron spectroscopy. The result suggested that transferring graphene on h-BN modified its work function, which changed field emission mechanism. Our report opens up a possibility of graphene-based vacuum nanoelectronics devices with tuned work function.

Yamada, Takatoshi, E-mail: takatoshi-yamada@aist.go.jp [National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Masuzawa, Tomoaki; Ebisudani, Taishi; Okano, Ken [International Christian University, 3-10-2 Osawa, Mitaka, Tokyo 181-8585 (Japan); Taniguchi, Takashi [National Institute for Material Science (NIMS), 1-1-1 Namiki, Tsukuba 305-0044 (Japan)

2014-06-02T23:59:59.000Z

322

Fast reverse osmosis using boron nitride and carbon nanotubes  

Science Journals Connector (OSTI)

We investigate reverse osmosis through commonly used polymeric and advanced inorganic nanotube based semipermeable membranes by performing nonequilibrium molecular dynamics simulations. Simulations indicate that there is a significantly higher water flux through boron-nitride nanotube (BNNT) and carbon nanotube(CNT) compared to a polymethyl methacrylate (PMMA) pore and a slightly higher water flux through BNNT as compared to CNT. The calculated permeation coefficient is in reasonable agreement with the theoretical single-file “hopping” model. Potential of mean force analysis indicates that the irregular nature of PMMA pore surface can cause significant localized energy barriers inside the pore thereby reducing the water flux.

M. E. Suk; A. V. Raghunathan; N. R. Aluru

2008-01-01T23:59:59.000Z

323

Aluminum nitride nanophotonic circuits operating at ultraviolet wavelengths  

SciTech Connect (OSTI)

Aluminum nitride (AlN) has recently emerged as a promising material for integrated photonics due to a large bandgap and attractive optical properties. Exploiting the wideband transparency, we demonstrate waveguiding in AlN-on-Insulator circuits from near-infrared to ultraviolet wavelengths using nanophotonic components with dimensions down to 40?nm. By measuring the propagation loss over a wide spectral range, we conclude that both scattering and absorption of AlN-intrinsic defects contribute to strong attenuation at short wavelengths, thus providing guidelines for future improvements in thin-film deposition and circuit fabrication.

Stegmaier, M.; Ebert, J.; Pernice, W. H. P., E-mail: wolfram.pernice@kit.edu [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76133 Karlsruhe (Germany); Meckbach, J. M.; Ilin, K.; Siegel, M. [Institute of Micro- und Nanoelectronic Systems, Karlsruhe Institute of Technology, 76187 Karlsruhe (Germany)

2014-03-03T23:59:59.000Z

324

Local environment of silicon in cubic boron nitride  

SciTech Connect (OSTI)

Si-doped cubic boron nitride (c-BN) is synthesized at high pressure and high temperature, and the local environment of Si is investigated using X-ray absorption near edge structure (XANES) and first-principles calculations. Si-K XANES indicates that Si in c-BN is surrounded by four nitrogen atoms. According to first-principles calculations, the model for substitutional Si at the B site well reproduces experimental Si-K XANES, and it is energetically more favorable than substitutional Si at the N site. Both the present experimental and theoretical results indicate that Si in c-BN prefers the B site to the N site.

Murata, Hidenobu, E-mail: MURATA.Hidenobu@nims.go.jp; Taniguchi, Takashi [Advanced Key Technologies Division, National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305–0044 (Japan); Hishita, Shunichi [Environment and Energy Materials Division, National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305–0044 (Japan); Yamamoto, Tomoyuki [Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169–8555 (Japan); Oba, Fumiyasu [Department of Materials Science and Engineering, Kyoto University, Yoshida-Honmachi, Sakyo, Kyoto 606–8501 (Japan); Tanaka, Isao [Department of Materials Science and Engineering, Kyoto University, Yoshida-Honmachi, Sakyo, Kyoto 606–8501 (Japan); Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta, Nagoya 456–8587 (Japan)

2013-12-21T23:59:59.000Z

325

Doping and isolation of GaN, InGaN and InAlN using ion implantation  

SciTech Connect (OSTI)

Both n- and p-type doping have been achieved in GaN using Si{sup +} or Mg{sup +}/P{sup +} implantation, respectively, followed annealing at {ge} 1050{degrees}C. Using proximity rapid thermal annealing (10sec) the GaN surface retains both smooth morphology and its original stoichiometry. Variable temperature Hall measurements reveal approximate energy levels of 62meV for the implanted Si and 171meV for the Mg, which are similar to their values in epitaxially grown GaN. Implant isolation of both n- and p-type GaN, and n-type In{sub 0.75}Al{sub 0.25}N with multiple energy inert species (e.g. N{sup +} or F{sup +}) produces high resistivity ({ge}10{sup 8}{omega}/{open_square}) after subsequent annealing in the range 600-700{degrees}C. Smaller increases in sheet resistance are observed for In{sub x}Ga{sup 1-x}N (x=0.33-0.75) under the same conditions due to the smaller energy bandgaps and the shallower energy levels of the damage-related states controlling the resistivity.

Pearton, S.J.; Vartuli, C.B.; Abernathy, C.R. [Univ. of Florida, Gainesville, FL (United States)] [and others

1995-08-01T23:59:59.000Z

326

Direct Measurement of Ion Beam Induced, Nanoscale Roughening of GaN Bentao Cui and P. I. Cohen  

E-Print Network [OSTI]

Direct Measurement of Ion Beam Induced, Nanoscale Roughening of GaN Bentao Cui and P. I. Cohen of a surface roughening term due to curvature-dependent sputtering or asymmetric attachment of vacancies change using atomic force microscopy, we show a method to measure the ion-roughening coefficient. Using

Cohen, Philip I.

327

K.K. Gan US ATLAS Pixel R&D Meeting 1 Results of Opto-Link R&D  

E-Print Network [OSTI]

&D Meeting 11 K.K. Gan 11 VCSEL Power vs Dosage AOC (5 & 10 Gb/s) survive to SLHC dosage 2007: Two arraysLight, Hamamatsu (new) GaAs: AOC, ULM, Optowell, Hamamatsu (new) VCSEL: AOC, Optowell, ULM

Gan, K. K.

328

Sensors and Actuators B 105 (2005) 329333 Remote sensing system for hydrogen using GaN Schottky diodes  

E-Print Network [OSTI]

including detection of combustion gases, for fuel leak detection in spacecraft, automobiles and aircraft satellites require thermal radiators to dissipate heat generated by the spacecraft elec- tronics hydrogen and hydrocarbons [1,7,24,25]. Gas sensors based on GaN could be integrated with high

Florida, University of

329

Role of Embedded Clustering in Dilute Magnetic Semiconductors: Cr Doped GaN X. Y. Cui,1  

E-Print Network [OSTI]

, typically 5 (20Ā­30) times smaller for Cr-based (Mn-based) III-V DMS than the value expected, 3 B= Cr4 BRole of Embedded Clustering in Dilute Magnetic Semiconductors: Cr Doped GaN X. Y. Cui,1 J. E configurations coexist and the statistical distribution and associated magnetism will depend sensitively

Medvedeva, Julia E.

330

A Comparison of Magnesium and Beryllium Acceptors in GaN Grown by rf-Plasma Assisted Molecular Beam Epitaxy  

E-Print Network [OSTI]

A Comparison of Magnesium and Beryllium Acceptors in GaN Grown by rf-Plasma Assisted Molecular Beam Evans and Associates, Sunnyvale, CA 94086 ABSTRACT Step-doped structures of both magnesium and beryllium activation energy of approximately 100 meV. INTRODUCTION While magnesium is currently the most

Myers, Tom

331

First-principles calculations of the structural and electronic properties of clean GaN(0001) surfaces  

Science Journals Connector (OSTI)

We employ density-functional theory (DFT) within the local-density approximation (LDA) and generalized-gradient approximation (GGA) to study structural and electronic properties of clean GaN(0001) surfaces. The pseudopotential method is used to investigate surfaces with (1×1), (2×2), and (3×3)R30° reconstructions. We also report calculations for the N2 molecule and for the bulk phases of Ga and GaN. We find that GGA give better results than LDA for the cohesive energies, but not for the structural properties. Bulk band structures are found to be very similar for both exchange-correlation potentials. Examining the clean GaN(0001) surfaces we conclude that both potentials give very similar relaxations and an almost identical dispersion for the surface states. We also report results for ionization energies, electron affinities, and work function for the GaN(0001) surfaces. As a general trend the ionization energy decreases monotonically with the increasing of the Ga-coverage.

A. L. Rosa and J. Neugebauer

2006-05-25T23:59:59.000Z

332

Local environment and composition of magnesium gallium layered double hydroxides determined from solid-state 1H and 71Ga NMR spectroscopy  

SciTech Connect (OSTI)

Ordering of gallium(III) in a series of magnesium gallium layered double hydroxides (LDH’s), [Mg1-xGax(OH)2(NO3)x yH2O], was determined using solid-state 1H and 71Ga NMR spectroscopy. Depletion of Ga in these LDH’s is demonstrated to be the result of soluble [Ga(OH)4]-complexes formed during synthesis.

Petersen, Line B.; Lipton, Andrew S.; Zorin, Vadim; Nielsen, Ulla Gro

2014-11-01T23:59:59.000Z

333

Nitride and Oxynitride Based Phosphors for Solid State Lighting  

SciTech Connect (OSTI)

The objective of the project is to advance the technology of the Lightscape Materials Inc. (Lightscape) proprietary nitride and oxynitride phosphors for solid state lighting (SSL) from the current level of maturity of applied research to advanced engineering development. This objective will be accomplished by optimizing the novel nitride and oxynitride phosphors, whose formulations are listed in Table 1, and establishing cost-effective preparation processes for the phosphors. The target performances of the phosphors are: • High luminescence efficiency: Quantum Yield = 90%. • Superior thermal stability of luminescence: Thermal Quenching Loss <10% at 150 °C. • Superior environmental stability: Luminescence Maintenance >90% after 5,000 hours at 85 °C and 85% relative humidity. • Scattering loss <10%. • Cost-effective preparation processes. The resulting phosphor materials and their preparation processes are anticipated to be a drop-in component for product development paths undertaken by LED lamp makers in the SSL industry. Upon program completion, Lightscape will target market insertion that enables high efficacy, high color rendering index (CRI), high thermal stability and long lifetime LED-based lighting products for general illumination that realizes substantial energy savings.

Tian, Yongchi

2011-10-15T23:59:59.000Z

334

Radiation tolerance of piezoelectric bulk single-crystal aluminum nitride  

SciTech Connect (OSTI)

For practical use in harsh radiation environments, we pose selection criteria for piezoelectric materials for nondestructive evaluation (NDE) and material characterization. Using these criteria, piezoelectric aluminum nitride is shown to be an excellent candidate. The results of tests on an aluminumnitride-based transducer operating in a nuclear reactor are also presented. We demonstrate the tolerance of single-crystal piezoelectric aluminum nitride after fast and thermal neutron fluences of 1.85 × 1018 neutron/cm2 and 5.8 × 1018 neutron/cm2, respectively, and a gamma dose of 26.8 MGy. The radiation hardness of AlN is most evident from the unaltered piezoelectric coefficient d33, which measured 5.5 pC/N after a fast and thermal neutron exposure in a nuclear reactor core for over 120 MWh, in agreement with the published literature value. The results offer potential for improving reactor safety and furthering the understanding of radiation effects on materials by enabling structural health monitoring and NDE in spite of the high levels of radiation and high temperatures, which are known to destroy typical commercial ultrasonic transducers.

David A. Parks; Bernhard R. Tittmann

2014-07-01T23:59:59.000Z

335

Origin of deep subgap states in amorphous indium gallium zinc oxide: Chemically disordered coordination of oxygen  

SciTech Connect (OSTI)

The origin of the deep subgap states in amorphous indium gallium zinc oxide (a-IGZO), whether intrinsic to the amorphous structure or not, has serious implications for the development of p-type transparent amorphous oxide semiconductors. We report that the deep subgap feature in a-IGZO originates from local variations in the oxygen coordination and not from oxygen vacancies. This is shown by the positive correlation between oxygen composition and subgap intensity as observed with X-ray photoelectron spectroscopy. We also demonstrate that the subgap feature is not intrinsic to the amorphous phase because the deep subgap feature can be removed by low-temperature annealing in a reducing environment. Atomistic calculations of a-IGZO reveal that the subgap state originates from certain oxygen environments associated with the disorder. Specifically, the subgap states originate from oxygen environments with a lower coordination number and/or a larger metal-oxygen separation.

Sallis, S.; Williams, D. S. [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States); Butler, K. T.; Walsh, A. [Center for Sustainable Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Quackenbush, N. F. [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Junda, M.; Podraza, N. J. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Fischer, D. A.; Woicik, J. C. [Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); White, B. E.; Piper, L. F. J., E-mail: lpiper@binghamton.edu [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

2014-06-09T23:59:59.000Z

336

Catalytic and physicochemical properties of aluminoplatinum catalysts modified with indium and gallium  

SciTech Connect (OSTI)

Aluminoplatinum catalysts (APC) are widely used in transformations of hydrocarbons, particularly in reforming of gasoline fractions and dehydrogenation of higher normal paraffins. Promotion of APC with indium and gallium increases their activity and stability in the dehydrogenation of paraffins. Introduction of group III elements in APC inhibits coke formation during dehydrogenation and prevents blocking of the surface of the Pt. The change in the catalytic properties of APC modified with In is due to the partial transfer of the electron density from Pt to In. Both APC with In and Ga additives and monometallic catalysts were studied in the present article by the methods of IR spectroscopy and adsorption. In addition to traditional transmission IR spectroscopy, IR spectroscopy in diffusely scattered light was used, which permits conducting both spectral and adsorption measurements on the same samples.

Zaitsev, A.V.; Tyupaev, A.P.; Borovkov, V.Yu.; Timofeeva, E.A.; Isatulyants, G.V.; Kazanskii, B.B.

1986-10-10T23:59:59.000Z

337

Plasma Sputter-type Ion Source with Wire Electrodes for Low-energy Gallium Ion Extraction  

SciTech Connect (OSTI)

Low-energy ions of gallium (Ga) and argon (Ar) were extracted from a plasma sputter-type ion source system that utilized a tungsten (W) wire extractor geometry. The 90% transparent W wire extractor configuration had shown that the system was capable of producing an ion beam with the energy as low as 10 eV in a dc filament discharge and 50 eV in a radio frequency (rf) excited system. In the present investigation, Ar plasma was sustained in an ion source chamber through an inductively coupled 13.56 MHz rf power source. Negatively biased liquid Ga target suspended on a W reservoir was sputtered and postionized prior to extraction. Mass spectral analyses revealed a strong dependence of the Ga{sup +} current on the induced target bias.

Vasquez, M. Jr.; Kasuya, T.; Wada, M. [Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); Maeno, S. [Novelion Systems Co. Ltd., Kyotanabe, Kyoto 610-0332 (Japan); Miyamoto, N. [Nissin Ion Equipment Co. Ltd., Minami-ku, Kyoto 601-8205 (Japan)

2011-01-07T23:59:59.000Z

338

The status of the solar neutrino problem and the Russian-American gallium experiment (SAGE)  

SciTech Connect (OSTI)

Perhaps the most outstanding discrepancy between prediction and measurements in current particle physics comes from the solar neutrino problem, in which a large deficit of high-energy solar neutrinos is observed. Many Nonstandard Solar Models have been invoked to try to reduce the predicted flux, but all have run into problems in trying to reproduce other measured parameters (e.g., the luminosity) of the Sun. Other explanations involving new physics such as neutrino decay and neutrino oscillations, etc. have also been proffered. Again, most of these explanations have been ruled out by either laboratory or astrophysical measurements. It appears that perhaps the most likely particle physics solution is that of matter enhanced neutrino oscillation, the Mikheyev-Smirnov-Wolfenstein (MSW) oscillations. Two new radiochemical gallium experiments, which have a low enough threshold to be sensitive to the dominant flux of low-energy p-p neutrinos, now also report a deficit and also favor a particle physics solution.

Bowles, T.J.

1994-04-01T23:59:59.000Z

339

Outdoor Performance of a Thin-Film Gallium-Arsenide Photovoltaic Module  

SciTech Connect (OSTI)

We deployed a 855 cm2 thin-film, single-junction gallium arsenide (GaAs) photovoltaic (PV) module outdoors. Due to its fundamentally different cell technology compared to silicon (Si), the module responds differently to outdoor conditions. On average during the test, the GaAs module produced more power when its temperature was higher. We show that its maximum-power temperature coefficient, while actually negative, is several times smaller in magnitude than that of a Si module used for comparison. The positive correlation of power with temperature in GaAs is due to temperature-correlated changes in the incident spectrum. We show that a simple correction based on precipitable water vapor (PWV) brings the photocurrent temperature coefficient into agreement with that measured by other methods and predicted by theory. The low operating temperature and small temperature coefficient of GaAs give it an energy production advantage in warm weather.

Silverman, T. J.; Deceglie, M. G.; Marion, B.; Cowley, S.; Kayes, B.; Kurtz, S.

2013-06-01T23:59:59.000Z

340

Solvent-Dependent Assembly of Terphenyl- and Quaterphenyldithiol on Gold and Gallium Arsenide  

Science Journals Connector (OSTI)

Solvent-Dependent Assembly of Terphenyl- and Quaterphenyldithiol on Gold and Gallium Arsenide ... This solvent pair was chosen because of an apparent solubility conflict:? while EtOH is the most common solvent for assembling alkylthiol and conjugated monothiol molecules,43-45 the longer n-phenyldithiols (n = 3, 4), in their thioacetyl forms (compounds 3 and 4 in Scheme 1), are poorly soluble in EtOH. ... The precipitate was filtered, washed with water, hexane, and methylene chloride, and dried overnight at 40 °C under vacuum to afford a light-yellow solid (5.90 g, 92%). 1H NMR (200 MHz, CDCl3) ? 7.65 (s, 4H), 7.55 (d, J = 8.0 Hz, 4H), 7.32 (d, J = 8.0 Hz, 4H), 2.55 (s, 6H). ...

Dmitry A. Krapchetov; Hong Ma; Alex K. Y. Jen; Daniel A. Fischer; Yueh-Lin Loo

2005-05-17T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Tunneling characteristics in chemical vapor deposited graphene–hexagonal boron nitride–graphene junctions  

SciTech Connect (OSTI)

Large area chemical vapor deposited graphene and hexagonal boron nitride was used to fabricate graphene–hexagonal boron nitride–graphene symmetric field effect transistors. Gate control of the tunneling characteristics is observed similar to previously reported results for exfoliated graphene–hexagonal boron nitride–graphene devices. Density-of-states features are observed in the tunneling characteristics of the devices, although without large resonant peaks that would arise from lateral momentum conservation. The lack of distinct resonant behavior is attributed to disorder in the devices, and a possible source of the disorder is discussed.

Roy, T.; Hesabi, Z. R.; Joiner, C. A.; Vogel, E. M. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332 (United States); Liu, L.; Gu, G. [Department of Electrical Engineering and Computer Science, University of Tennessee, 1520 Middle Drive, Knoxville, Tennessee 37996 (United States); Barrera, S. de la; Feenstra, R. M. [Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States); Chakrabarti, B. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332 (United States); Department of Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Rd., Richardson, Texas 75080 (United States)

2014-03-24T23:59:59.000Z

342

Effects of surface treatment using aqua regia solution on the change of surface band bending of p-type GaN  

Science Journals Connector (OSTI)

Effects of surface treatment on the change of band bending at the surface of p-type GaN were studied using ... interpret the reduction of contact resistivity by the surface treatment. The contact resistivity on p...

Jong Kyu Kim; Ki-Jeong Kim; Bongsoo Kim; Jae Nam Kim…

2001-01-01T23:59:59.000Z

343

Annealing of the radiation damage in Mg-implanted GaN thin films: Temperature development of lattice parameters and stresses  

Science Journals Connector (OSTI)

Heteroepitaxial GaN thin films implanted with Mg ions with a concentration of 1.3 × 1019 cm?3 are analyzed using in-situ X-ray diffraction in the temperature range of 20–700 °C. The temperature dependence of unstressed lattice parameters and stresses in the implanted films is evaluated and compared with the results from a virgin GaN thin film. The measurements indicate that the annealing of the radiation damage in the implanted GaN is accompanied by a unique temperature hysteresis of the GaN structural characteristics and the main part of the radiation damage is removed during heating in the temperature range of 100–300 °C. The temperature of 1620 °C is extrapolated as an important annealing limit in order to significantly decrease implantation-induced disorder in the films.

J. Keckes; A. Wenzel; J.W. Gerlach; B. Rauschenbach

2003-01-01T23:59:59.000Z

344

Boron-Nitride (BN) Nanotubes (BNNT) at TJNAF| U.S. DOE Office of Science  

Office of Science (SC) Website

Boron-Nitride (BN) Nanotubes (BNNT) at Boron-Nitride (BN) Nanotubes (BNNT) at TJNAF Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information Ā» Spinoff Archives Boron-Nitride (BN) Nanotubes (BNNT) at TJNAF Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: Boron-Nitride (BN) Nanotubes (BNNT) Developed at: Jefferson Lab Free Electron Facility Developed in: 2008-2011

345

Friction and wear behavior of in-situ reinforced silicon nitride. Final report  

SciTech Connect (OSTI)

Specimens of in-situ-reinforced silicon nitride (ISRSH) have been wear tested in lubricated, reciprocating, sliding motion against a silicon nitride counterface. Only mild wear of the ISRSN was observed at contact pressures up to 4.8 GPa at an average sliding velocity of 0.3 m/s. At 0.6 m/s, a wear mode transition was observed in ISRSN at 4.2 - 4.4 GPa. In comparison, the wear mode transition in silicon carbide whisker reinforced silicon nitride at both velocities was evident at about 2.2 - 2.4 GPa. Scanning electron microscopy of the ISRSN wear surfaces revealed the presence of a 40 pm thick debris layer on the mild wear tracks. The ISRSN wear mode transition response indicated a potential for an improved wear resistance in this material as compared to whisker reinforced silicon nitride.

Yust, C.S.

1995-10-01T23:59:59.000Z

346

Method of nitriding, carburizing, or oxidizing refractory metal articles using microwaves  

DOE Patents [OSTI]

A method of nitriding an article of refractory-nitride-forming metal or metalloids. A consolidated metal or metalloid article is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid to an article of refractory nitride. in addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

Holcombe, C.E.; Dykes, N.L.; Tiegs, T.N.

1992-10-13T23:59:59.000Z

347

Method of nitriding, carburizing, or oxidizing refractory metal articles using microwaves  

DOE Patents [OSTI]

A method of nitriding an article of refractory-nitride-forming metal or metalloids. A consolidated metal or metalloid article is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid to an article of refractory nitride. in addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

Holcombe, Cressie E. (Knoxville, TN); Dykes, Norman L. (Oak Ridge, TN); Tiegs, Terry N. (Lenoir City, TN)

1992-01-01T23:59:59.000Z

348

E-Print Network 3.0 - argon nitrides Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

I?MAYR Sti+ng Institutfur Werkstofiechnik... ,Badgasteiner Str: 3, 2800Bremen 33, Germany Abstract Aluminium nitride (AlN) is a ve interestin ceramic because... the use %of...

349

Lasers Used to Make First Boron-Nitride Nanotube Yarn | Jefferson...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Yarn Visualization of helium-4 and beryllium nuclei. A yarn spun of boron-nitride nanotubes suspends a quarter. NEWPORT NEWS, VA, Dec. 2 -Researchers have used lasers to create...

350

High-Temperature Oxidation Resistance of Refractory Silicon Nitride—Silicon Carbide Materials  

Science Journals Connector (OSTI)

Silicon nitride and carbide are promising materials for use as refractories; they are highly resistant to mineral acids and alkalis, have a high melting point, and are thermally very stable [1].

I. N. Godovannaya; O. I. Popova

1972-01-01T23:59:59.000Z

351

Optoelectronic Properties in Monolayers of Hybridized Graphene and Hexagonal Boron Nitride  

E-Print Network [OSTI]

We explain the nature of the electronic energy gap and optical absorption spectrum of carbon–boron-nitride (CBN) monolayers using density functional theory, GW and Bethe-Salpeter calculations. The band structure and the ...

Bernardi, Marco

352

Hydrogen adsorption on boron nitride nanotubes: A path to room-temperature hydrogen storage  

Science Journals Connector (OSTI)

The adsorption of molecular hydrogen on boron nitride nanotubes is studied with the use of the pseudopotential density functional method. The binding energy and distance of adsorbed hydrogen is particularly calculated. It is found that the binding energy of hydrogen on boron nitride nanotubes is increased by as much as 40% compared to that on carbon nanotubes, which is attributed to heteropolar bonding in boron nitride. The effect of substitutional doping and structural defects on hydrogen adsorption is also studied and we find a substantial enhancement of the binding energy from that on perfect boron nitride. The current study demonstrates a pathway to the finding of proper media that can hold hydrogen at ambient conditions through physisorption.

Seung-Hoon Jhi and Young-Kyun Kwon

2004-06-22T23:59:59.000Z

353

Fluorination of a depleted uranium-plutonium-nitride fuel with elemental fluorine  

Science Journals Connector (OSTI)

A physical and a mathematical model have been developed to describe the physicochemical process of torch fluorination of an uranium-plutonium-nitride fuel. An algorithm for calculating the velocity, temperatur...

V. A. Karelin; V. N. Brendakov; M. V. Popadeikin

354

Method of enhancing the wettability of boron nitride for use as an electrochemical cell separator  

DOE Patents [OSTI]

A felt or other fabric of boron nitride suitable for use as an interelecte separator within an electrochemical cell is wetted with a solution containing a thermally decomposable organic salt of an alkaline earth metal. An aqueous solution of magnesium acetate is the preferred solution for this purpose. After wetting the boron nitride, the solution is dried by heating at a sufficiently low temperature to prevent rapid boiling and the creation of voids within the separator. The dried material is then calcined at an elevated temperature in excess of 400.degree. C. to provide a coating of an oxide of magnesium on the surface of the boron nitride fibers. A fabric or felt of boron nitride treated in this manner is easily wetted by molten electrolytic salts, such as the alkali metal halides or alkaline earth metal halides, that are used in high temperature, secondary electrochemical cells.

McCoy, Lowell R. (Woodland Hills, CA)

1982-01-01T23:59:59.000Z

355

Method of enhancing the wettability of boron nitride for use as an electrochemical cell separator  

DOE Patents [OSTI]

A felt or other fabric of boron nitride suitable for use as an interelectrode separator within an electrochemical cell is wetted with a solution containing a thermally decomposable organic salt of an alkaline earth metal. An aqueous solution of magnesium acetate is the preferred solution for this purpose. After wetting the boron nitride, the solution is dried by heating at a sufficiently low temperature to prevent rapid boiling and the creation of voids within the separator. The dried material is then calcined at an elevated temperature in excess of 400/sup 0/C to provide a coating of an oxide of magnesium on the surface of the boron nitride fibers. A fabric or felt of boron nitride treated in this manner is easily wetted by molten electrolytic salts, such as the alkali metal halides or alkaline earth metal halides, that are used in high temperature, secondary electrochemical cells.

McCoy, L.R.

1981-01-23T23:59:59.000Z

356

E-Print Network 3.0 - aluminium nitrides Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

111,Volume 3, novembre 1993 Summary: ,Badgasteiner Str: 3, 2800Bremen 33, Germany Abstract Aluminium nitride (AlN) is a ve interestin ceramic because... the use %of lasma...

357

Impurity-induced disorder in III-nitride materials and devices  

DOE Patents [OSTI]

A method for impurity-induced disordering in III-nitride materials comprises growing a III-nitride heterostructure at a growth temperature and doping the heterostructure layers with a dopant during or after the growth of the heterostructure and post-growth annealing of the heterostructure. The post-growth annealing temperature can be sufficiently high to induce disorder of the heterostructure layer interfaces.

Wierer, Jr., Jonathan J; Allerman, Andrew A

2014-11-25T23:59:59.000Z

358

Surface hardening of metallic alloys by electrospark deposition followed by plasma nitriding  

Science Journals Connector (OSTI)

This paper presents the results of a study concerned with the surface hardening of nonferrous and ferrous alloys, by integrating the electrospark deposition and plasma nitriding processes. Specimens of an aluminium bronze and of a grey cast iron were firstly electrospark coated with AISI-304 stainless steel and, then, ion nitrided in a 25%N2 + 75%H2 dc plasma. It is shown that by using these two treatments, the surface hardness of this two materials can be substantially increased.

M.A. Béjar; W. Schnake; W. Saavedra; J.P. Vildósola

2006-01-01T23:59:59.000Z

359

Investigations of chemical vapor deposition of GaN using synchrotron radiation  

SciTech Connect (OSTI)

The authors apply synchrotron x-ray analysis techniques to probe the surface structure of GaN films during synthesis by metal-organic chemical vapor deposition (MOCVD). Their approach is to observe the evolution of surface structure and morphology in real time using grazing incidence x-ray scattering (GIXS). This technique combines the ability of x-rays to penetrate the chemical vapor deposition environment for in situ measurements, with the sensitivity of GIXS to atomic scale structure. In this paper they present examples from some of their studies of growth modes and surface evolution as a function of process conditions that illustrate the capabilities of synchrotron x-ray analysis during MOCVD growth. They focus on studies of the homoepitaxial growth mode, island coarsening dynamics, and effects of impurities.

Thompson, C.; Stephenson, G. B.; Eastman, J. A.; Munkholm, A.; Auciello, O.; Murty, M. V. R.; Fini, P.; DenBaars, S. P.; Speck, J. S.

2000-05-25T23:59:59.000Z

360

Structural Properties of Eu-Doped GaN Investigated by Raman Spectroscopy  

SciTech Connect (OSTI)

Rare-earth (RE) impurities doped GaN are highly promising candidates for light emitting device applications due to their efficient electroluminescence properties at room temperature. Among those, Eu doped GaN has been identified as an excellent material for the red spectral region due to its strong emission at 620 nm. As a transition internal to the Eu doping atom (4f-4f), light emission originates in a much smaller complex than the more flexibly controllable quantum structures of wells, wires, and dots. This is thought to make the center less susceptible to structural defects and in particular radiation damage in the lattice host. Nevertheless, the lattice host is crucial for providing the excitation in from of free electrons and holes. In this respect, the actual lattice site Eu occupies in the host lattice, i.e. in GaN, is important. A large fraction of Eu atoms are typically inactive which must be attributed to their lattice site and local environment. GaN films implanted with Eu to concentrations of {approx}10{sup 18} cm{sup -3} were subjected to a highly directed beam of 500 keV He{sup +} at a dose of 5 x 10{sup 14} cm{sup -2}. By means of a shadow mask, irradiated and unexposed regions lie very close to each other on the same sample. We used optical and structural analysis to identify the exerted radiation damage. At the full radiation dose, photoluminescence intensity has decayed to {approx}0.01 of its initial value. From the dose dependence of the radiation decay we previously concluded, that this decay is in part due to the destruction of radiative Eu sites [J.W. Tringe, unpublished (2006)]. Along the transition from virgin to irradiated material we analyze the accumulated damage in terms of surface morphology (atomic force microscopy), crystallinity (x-ray diffraction), and phonon dispersion using micro-Raman spectroscopy. In addition to the well-studied E{sub 2}(high) mode, two new vibrational modes at 659 cm{sup -1} and 201 cm{sup -1} were observed in the Eu implanted and annealed sample, prior to He{sup +} irradiation. These modes are either remnants of the implantation damage or related to the Eu impurity. As such they can be indicative of the actual lattice site the Eu atom resides on. After irradiation, broad Raman modes at 300 cm-1 are being observed. This band indicates disorder activated Raman scattering (DARS) due to the radiation damage. An additional narrow mode appears at 672 cm{sup -1}, which can possibly be due to a nitrogen vacancy related vibrational mode. The continuous transition from irradiated to un-irradiated sample allows the direct evolution of radiation damage and its coordinated effects in structural, optical and vibrational properties. By its systematic correlation we anticipate to be able to elucidate the Eu lattice interaction and the processes of radiation damage.

Senawiratne, J; Xia, Y; Detchprohm, T; Tringe, J W; Stevens, C G; Wetzel, C

2006-06-20T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Nitride III-V Activities at Sandia National Labs  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Lighting: Lighting: Synergisms with Office of Science Materials Programs Jerry A. Simmons Semiconductor Materials and Device Sciences Sandia National Laboratories March 13, 2001 EMaCC Meeting OUTLINE *Brief overview of prospects & promise of SSL *National Initiative *Grand Challenge LDRD at Sandia *BES-supported activities at Sandia provided core capabilities *Other NS applications of nitride materials science Will only discuss inorganic materials and devices here. Major motivation for SSL is energy savings: lighting is large fraction of energy consumption 1 10 100 1000 1970 1980 1990 2000 2010 2020 Energy Electricity Illumination (assuming 20% of electricity) Projected WORLD Energy Consumption (Quads) Year 400 Quads 130 Quads 25 Quads 1998 1970 1980 1990 2000 2010 2020 Energy Electricity Illumination

362

Graphene interconnects fully encapsulated in layered insulator hexagonal boron nitride  

Science Journals Connector (OSTI)

We demonstrate improvements in the electrical performance of graphene interconnects with full encapsulation by lattice-matching layered insulator, hexagonal boron nitride (h-BN). A novel layer-based transfer method is developed to assemble the top passivating layer of h-BN on the graphene surface to construct the h-BN/graphene/h-BN heterostructures. The encapsulated graphene interconnects (EGIs) are characterized and compared with graphene interconnects on either SiO2 or h-BN substrates with no top passivating h-BN layer. We observe significant improvements in both the maximum current density and breakdown voltage in EGIs. Compared with the uncovered structures, EGIs also show an appreciable increase (~67%) in power density at breakdown. These improvements are achieved without degrading the carrier transport characteristics in graphene wires. In addition, EGIs exhibit a minimal environment impact, showing electrical behavior insensitive to ambient conditions.

Nikhil Jain; Chris A Durcan; Robin Jacobs-Gedrim; Yang Xu; Bin Yu

2013-01-01T23:59:59.000Z

363

Single-layer graphene on silicon nitride micromembrane resonators  

SciTech Connect (OSTI)

Due to their low mass, high quality factor, and good optical properties, silicon nitride (SiN) micromembrane resonators are widely used in force and mass sensing applications, particularly in optomechanics. The metallization of such membranes would enable an electronic integration with the prospect for exciting new devices, such as optoelectromechanical transducers. Here, we add a single-layer graphene on SiN micromembranes and compare electromechanical coupling and mechanical properties to bare dielectric membranes and to membranes metallized with an aluminium layer. The electrostatic coupling of graphene covered membranes is found to be equal to a perfectly conductive membrane, without significantly adding mass, decreasing the superior mechanical quality factor or affecting the optical properties of pure SiN micromembranes. The concept of graphene-SiN resonators allows a broad range of new experiments both in applied physics and fundamental basic research, e.g., for the mechanical, electrical, or optical characterization of graphene.

Schmid, Silvan; Guillermo Villanueva, Luis; Amato, Bartolo; Boisen, Anja [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, 2800 Kongens Lyngby (Denmark); Bagci, Tolga; Zeuthen, Emil; Sųrensen, Anders S.; Usami, Koji; Polzik, Eugene S. [QUANTOP, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Taylor, Jacob M. [Joint Quantum Institute/NIST, College Park, Maryland 20899 (United States); Herring, Patrick K.; Cassidy, Maja C. [School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts 02138 (United States); Marcus, Charles M. [Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Cheol Shin, Yong; Kong, Jing [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2014-02-07T23:59:59.000Z

364

Spectroscopic ellipsometry characterization of thin-film silicon nitride  

SciTech Connect (OSTI)

We have measured and analyzed the optical characteristics of a series of silicon nitride thin films prepared by plasma-enhanced chemical vapor deposition on silicon substrates for photovoltaic applications. Spectroscopic ellipsometry measurements were made by using a two-channel spectroscopic polarization modulator ellipsometer that measures N, S, and C data simultaneously. The data were fit to a model consisting of air / roughness / SiN / crystalline silicon. The roughness was modeled using the Bruggeman effective medium approximation, assuming 50% SiN, 50% voids. The optical functions of the SiN film were parameterized using a model by Jellison and Modine. All the {Chi}{sup 2} are near 1, demonstrating that this model works extremely well for all SiN films. The measured dielectric functions were used to make optimized SiN antireflection coatings for crystalline silicon solar cells.

Jellison, G.E. Jr.; Modine, F.A. [Oak Ridge National Lab., TN (United States); Doshi, P.; Rohatgi, A. [Georiga Inst. of Technology, Atlanta, GA (United States)

1997-05-01T23:59:59.000Z

365

Reference Data for the Density and Viscosity of Liquid Cadmium, Cobalt, Gallium, Indium, Mercury, Silicon, Thallium, and Zinc  

SciTech Connect (OSTI)

The available experimental data for the density and viscosity of liquid cadmium, cobalt, gallium, indium, mercury, silicon, thallium, and zinc have been critically examined with the intention of establishing both a density and a viscosity standard. All experimental data have been categorized into primary and secondary data according to the quality of measurement, the technique employed and the presentation of the data, as specified by a series of criteria. The proposed standard reference correlations for the density of liquid cadmium, cobalt, gallium, indium, silicon, thallium, and zinc are characterized by percent deviations at the 95% confidence level of 0.6, 2.1, 0.4, 0.5, 2.2, 0.9, and 0.7, respectively. In the case of mercury, since density reference values already exist, no further work was carried out. The standard reference correlations for the viscosity of liquid cadmium, cobalt, gallium, indium, mercury, silicon, thallium, and zinc are characterized by percent deviations at the 95% confidence level of 9.4, 14.0, 13.5, 2.1, 7.3, 15.7, 5.1, and 9.3, respectively.

Assael, Marc J.; Armyra, Ivi J.; Brillo, Juergen; Stankus, Sergei V.; Wu Jiangtao; Wakeham, William A. [Chemical Engineering Department, Aristotle University, 54124 Thessaloniki (Greece); Institut fuer Materialphysik im Weltraum, Deutsches Zentrum fuer Luft- und Raumfahrt, 51170 Koeln (Germany); Kutateladze Institute of Thermophysics, Siberian Brunch of the Russian Academy of Sciences, Lavrentyev ave. 1, 630090 Novosibirsk (Russian Federation); Center of Thermal and Fluid Science, School of Energy and Power Engineering, Xi'an Jiaotong University, Shaanxi 710049 (China); Chemical Engineering Department, Imperial College, London SW7 2BY (United Kingdom)

2012-09-15T23:59:59.000Z

366

Evaluation of critical materials for five advanced design photovoltaic cells with an assessment of indium and gallium  

SciTech Connect (OSTI)

The objective of this study is to identify potential material supply constraints due to the large-scale deployment of five advanced photovoltaic (PV) cell designs, and to suggest strategies to reduce the impacts of these production capacity limitations and potential future material shortages. This report presents the results of the screening of the five following advanced PV cell designs: polycrystalline silicon, amorphous silicon, cadmium sulfide/copper sulfide frontwall, polycrystalline gallium arsenide MIS, and advanced concentrator-500X. Each of these five cells is screened individually assuming that they first come online in 1991, and that 25 GWe of peak capacity is online by the year 2000. A second computer screening assumes that each cell first comes online in 1991 and that each cell has 5 GWe of peak capacity by the year 2000, so that the total online cpacity for the five cells is 25 GWe. Based on a review of the preliminary basline screening results, suggestions were made for varying such parameters as the layer thickness, cell production processes, etc. The resulting PV cell characterizations were then screened again by the CMAP computer code. Earlier DOE sponsored work on the assessment of critical materials in PV cells conclusively identtified indium and gallium as warranting further investigation as to their availability. Therefore, this report includes a discussion of the future availability of gallium and indium. (WHK)

Watts, R.L.; Gurwell, W.E.; Jamieson, W.M.; Long, L.W.; Pawlewicz, W.T.; Smith, S.A.; Teeter, R.R.

1980-05-01T23:59:59.000Z

367

Biofuels production from hydrotreating of vegetable oil using supported noble metals, and transition metal carbide and nitride.  

E-Print Network [OSTI]

?? The focus of this research is to prepare non-sulfided hydrotreating catalysts, supported noble metal and transition metal carbide/ nitride, and evaluate their hydrocracking activities… (more)

Wang, Huali

2012-01-01T23:59:59.000Z

368

Study of gain and photoresponse characteristics for back-illuminated separate absorption and multiplication GaN avalanche photodiodes  

SciTech Connect (OSTI)

The gain and photoresponse characteristics have been numerically studied for back-illuminated separate absorption and multiplication (SAM) GaN avalanche photodiodes (APDs). The parameters of fundamental models are calibrated by simultaneously comparing the simulated dark and light current characteristics with the experimental results. Effects of environmental temperatures and device dimensions on gain characteristics have been investigated, and a method to achieve the optimum thickness of charge layer is obtained. The dependence of gain characteristics and breakdown voltage on the doping concentration of the charge layer is also studied in detail to get the optimal charge layer. The bias-dependent spectral responsivity and quantum efficiency are then presented to study the photoresponse mechanisms inside SAM GaN APDs. It is found the responsivity peak red-shifts at first due to the Franz-Keldysh effect and then blue-shifts due to the reach-through effect of the absorption layer. Finally, a new SAM GaN/AlGaN heterojunction APD structure is proposed for optimizing SAM GaN APDs.

Wang, Xiaodong; Pan, Ming; Hou, Liwei; Xie, Wei [No. 50 Research Institute of China Electronics Technology Group Corporation, 200331 Shanghai (China); Hu, Weida, E-mail: wdhu@mail.sitp.ac.cn; Xu, Jintong; Li, Xiangyang; Chen, Xiaoshuang, E-mail: xschen@mail.sitp.ac.cn; Lu, Wei [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 200083 Shanghai (China)

2014-01-07T23:59:59.000Z

369

Electrodeposition of Crystalline GaAs on Liquid Gallium Electrodes in Aqueous Electrolytes  

Science Journals Connector (OSTI)

Crystalline gallium arsenide (c-GaAs) possesses many desirable optoelectronic properties suited for solar energy conversion,(1) light and radiation detection,(2) chemical sensing,(3) lighting,(4) and high speed electronics. ... In contrast to conflicting previous reports on the electrodeposition of GaAs,(17, 18) we posit that c-GaAs(s) can be synthesized predictably through the electrodeposition of As from dissolved As2O3 specifically on a Ga(l) electrode at modest temperatures in water. ... Specifically, for any binary system composed of a solid dissolving into a liquid, the rate of dissolution of the solid into the liquid phase is given by eq 5:(60)(5)where kdiss is the dissolution rate constant, s is the surface area of the solid in contact with the liquid, V is the volume of the liquid, Csat is the solubility of the solid in the liquid, and Cdiss is the concentration of the dissolved solid in the bulk of the liquid phase. ...

Eli Fahrenkrug; Junsi Gu; Stephen Maldonado

2012-12-24T23:59:59.000Z

370

Reaction injection molding of silicon nitride ceramics having crystallized grain boundary phases  

SciTech Connect (OSTI)

A reaction injection molding process is described for preparing a sintered, silicon nitride-containing ceramic article comprising; (1) injecting into a heated mold a fluid, nondilatant mixture comprising (a) at least 40% by volume of a powder mixture of (i) from about 20 wt.% to about 98 wt.% silicon nitride, (ii) from about 0.5 wt.% to about 20 wt.% of a silicate glass-forming sintering aid, and (iii) from about 0.001 wt.% to about 80 wt.% of a high metal content transition metal silicide or a transition metal or metal compound that forms a high metal content silicide with silicon nitride under the conditions defined in steps (2) or (3), and (b) a curable silicon nitride precursor binder that is a liquid below its curing temperature, to cure the binder and produce a hardened molded article, (2) heating the hardened mol suitable atmosphere to a temperature sufficient to convert the cured binder to a silicon nitride-containing ceramic, and (3) sintering the article by (i) heating at a temperature of 1,300 to 1,800 C until a silicate glass forms, and (ii) further heating at a temperature of 1,300 to 1,800 C under a vacuum until oxygen is removed from the silicate glass and the glass crystallizes.

Lukacs, A. III; Matsumoto, R.L.K.

1993-08-31T23:59:59.000Z

371

Process for producing silicon nitride based articles of high fracture toughness and strength  

DOE Patents [OSTI]

A process for producing a silicon nitride-based article of improved fracture toughness and strength. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12 m.sup.2 /g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

Huckabee, Marvin (Marlboro, MA); Buljan, Sergej-Tomislav (Acton, MA); Neil, Jeffrey T. (Acton, MA)

1991-01-01T23:59:59.000Z

372

Process for producing silicon nitride based articles of high fracture toughness and strength  

DOE Patents [OSTI]

A process for producing a silicon nitride-based article of improved fracture toughness and strength is disclosed. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12 m[sup 2]/g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

Huckabee, M.; Buljan, S.T.; Neil, J.T.

1991-09-10T23:59:59.000Z

373

Examination on surface films of plasma nitrided and post-stream oxidised H13 steel  

Science Journals Connector (OSTI)

Different surface structures have been obtained on H13 steel by plasma nitriding under a mix current of ammonia and argon at 520Ā°C, and a simple current of ammonia at 550Ā°C. Post-stream oxidation gives the H13 samples a compact oxide film. The surface films and structures of these samples have been investigated with optical microscopy, X-ray diffraction, scanning electron microscopy and high distinguishability energy diffraction spectrometry. Only a single nitrogen diffusion layer is obtained on the 520Ā°C-nitrided H13 samples, while a white Fe2-3N nitride film and a deeper diffusion layer with needle-like nitride is obtained on the 550Ā°C-nitrided samples. These two type samples are covered by the films of Me3O4 mainly as well as Fe2O3 after post-oxidation. It is also discussed on the application chances of the duplex treatment, which is cleaner and more environment friendly than conventional salt bath or gaseous techniques.

Yongan Min; Xiaochun Wu; Luoping Xu

2008-01-01T23:59:59.000Z

374

SUMMARY ON TITANIUM NITRIDE COATING OF SNS RING VACUUM CHAMBERS.  

SciTech Connect (OSTI)

The inner surfaces of the 248 m Spallation Neutron Source (SNS) accumulator ring vacuum chambers are coated with {approx}100nm of titanium nitride (TiN) to reduce the secondary electron yield (SEY) of the chamber walls. There are approximately 135 chambers and kicker modules, some up to 5m in length and 36cm in diameter, coated with TiN. The coating is deposited by means of reactive DC magnetron sputtering -using a - cylindrical cathode with internal permanent magnets. This cathode configuration generates a deposition-rate sufficient to meet the required production schedule and produces stoichiometric films with good adhesion, low SEY and acceptable outgassing. Moreover, the cathode magnet configuration allows for simple changes in length and has been adapted to coat the wide variety of chambers and components contained within the arcs, injection, extraction, collimation and RF straight sections. Chamber types and quantities as well as the cathode configurations are presented herein. The unique coating requirements of the injection kicker ceramic chambers and the extraction kicker ferrite surface will be emphasized. A brief summary of the salient coating properties is given including the interdependence of SEY as a function of surface roughness and its effect on outgassing.

TODD, R.; HE, P.; HSEUH, H.C.; WEISS, D.

2005-05-16T23:59:59.000Z

375

Radial elasticity of multi-walled boron nitride nanotubes  

SciTech Connect (OSTI)

We investigated the radial mechanical properties of multi-walled boron nitride nanotubes (MW-BNNTs) using atomic force microscopy. The employed MW-BNNTs were synthesized using pressurized vapor/condenser (PVC) methods and were dispersed in aqueous solution using ultrasonication methods with the aid of ionic surfactants. Our nanomechanical measurements reveal the elastic deformational behaviors of individual BNNTs with two to four tube walls in their transverse directions. Their effective radial elastic moduli were obtained through interpreting their measured radial deformation profiles using Hertzian contact mechanics models. Our results capture the dependences of the effective radial moduli of MW-BNNTs on both the tube outer diameter and the number of tube layers. The effective radial moduli of double-walled BNNTs are found to be several-fold higher than those of single-walled BNNTs within the same diameter range. Our work contributes directly to a complete understanding of the fundamental structural and mechanical properties of BNNTs and the pursuits of their novel structural and electronics applications.

Michael W. Smith, Cheol Park, Meng Zheng, Changhong Ke ,In-Tae Bae, Kevin Jordan

2012-02-01T23:59:59.000Z

376

III-nitride core–shell nanowire arrayed solar cells  

Science Journals Connector (OSTI)

A solar cell based on a hybrid nanowire–film architecture consisting of a vertically aligned array of InGaN/GaN multi-quantum well core–shell nanowires which are electrically connected by a coalesced p-InGaN canopy layer is demonstrated. This unique hybrid structure allows for standard planar device processing, solving a key challenge with nanowire device integration, while enabling various advantages by the nanowire absorbing region such as higher indium composition InGaN layers by elastic strain relief, more efficient carrier collection in thinner layers, and enhanced light trapping from nano-scale optical index changes. This hybrid structure is fabricated into working solar cells exhibiting photoresponse out to 2.1 eV and short-circuit current densities of ~1 mA cm?2 under 1 sun AM1.5G. This proof-of-concept nanowire-based device demonstrates a route forward for high-efficiency III-nitride solar cells.

Jonathan J Wierer Jr; Qiming Li; Daniel D Koleske; Stephen R Lee; George T Wang

2012-01-01T23:59:59.000Z

377

Spatial distribution and magnetism in poly-Cr-doped GaN from first principles X. Y. Cui,1 J. E. Medvedeva,2 B. Delley,3 A. J. Freeman,4 and C. Stampfl1  

E-Print Network [OSTI]

Spatial distribution and magnetism in poly-Cr-doped GaN from first principles X. Y. Cui,1 J. E the spatial distribution and magnetic coupling of Cr-doped GaN, in which exhaustive structural and magnetic direct evidence that the distribution of the doped magnetic ions is neither homogeneous nor random

Medvedeva, Julia E.

378

The different adsorption mechanism of methane molecule onto a boron nitride and a graphene flakes  

SciTech Connect (OSTI)

Graphene and single layer hexagonal boron-nitride are two newly discovered 2D materials with wonderful physical properties. Using density functional theory, we study the adsorption mechanism of a methane molecule over a hexagonal flake of single layer hexagonal boron-nitride (h-BN) and compare the results with those of graphene. We found that independent of the used functional in our ab-initio calculations, the adsorption energy in the h-BN flake is larger than that for graphene. Despite of the adsorption energy profile of methane over a graphene flake, we show that there is a long range behavior beyond minimum energy in the adsorption energy of methane over h-BN flake. This result reveals the higher sensitivity of h-BN sheet to the adsorption of a typical closed shell molecule with respect to graphene. The latter gives insight in the recent experiments of graphene over hexagonal boron nitride.

Seyed-Talebi, Seyedeh Mozhgan [Shahid Chamran University, Golestan boulevard, Ahvaz, Khouzestan (Iran, Islamic Republic of); Neek-Amal, M., E-mail: neekamal@srttu.edu [Shahid Rajaee Teacher Training University, Lavizan, Tehran (Iran, Islamic Republic of)

2014-10-21T23:59:59.000Z

379

Formation of Protective Nitride Surfaces for PEM Fuel Cell Metallic Bipolar Plates  

SciTech Connect (OSTI)

Selective gas nitridation of model Ni-base alloys was used to form dense, electrically-conductive and corrosion-resistant nitride surface layers, including TiN, VN, CrN, Cr2N, as well as a complex NiNbVN phase. Evaluation for use as a protective surface for metallic bipolar plates in proton exchange membrane fuel cells (PEMFC) indicated that CrN/Cr2N base surfaces hold promise to meet Department of Energy (DOE) performance goals for automotive applications. The thermally grown CrN/Cr2N surface formed on model Ni-Cr base alloys exhibited good stability and low electrical resistance in single-cell fuel cell testing under simulated drive-cycle conditions. Recent results indicate that similar protective Cr-nitride surfaces can be formed on less expensive Fe-Cr base alloys potentially capable of meeting DOE cost goals.

Brady, Michael P [ORNL; Yang, Bing [ORNL; Wang, Heli [National Renewable Energy Laboratory (NREL); Turner, John [National Renewable Energy Laboratory (NREL); More, Karren Leslie [ORNL; Wilson, Mahlon [Los Alamos National Laboratory (LANL); Garzon, Fernando [Los Alamos National Laboratory (LANL)

2006-01-01T23:59:59.000Z

380

Thermodynamic stability and unusual strength of ultra-incompressible rhenium nitrides  

SciTech Connect (OSTI)

We report on a comprehensive study of thermodynamic and mechanical properties as well as a bond-deformation mechanism on ultra-incompressible Re{sub 2} N and Re{sub 3} N. The introduction of nitrogen into the rhenium lattice leads to thermodynamic instability in Re{sub 2} N at ambient conditions and enhanced incompressibility and strength for both rhenium nitrides. Rhenium nitrides, however, show substantially lower ideal shear strength than hard ReB{sub 2} and superhard c -BN, suggesting that they cannot be intrinsically superhard. An intriguing soft “ionic bond mediated plastic deformation” mechanism is revealed to underline the physical origin of their unusual mechanical strength. These results suggest a need to reformulate the design concept of intrinsically superhard transition-metal nitrides, borides, and carbides.

Zhang, R. F.; Lin, Zhijun; Mao, Ho-kwang; Zhao, Yusheng

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Temperature dependence of photoconductivity in Zn-doped GaN  

SciTech Connect (OSTI)

In agreement with predictions from a model that explained an abrupt thermal quenching of the blue luminescence (BL) band in high-resistivity Zn-doped GaN [Reshchikov et al., Phys. Rev. B 84, 075212 (2011) and Phys. Rev. B 85, 245203 (2012)], we observed the stepwise decrease of photoconductivity in this material with increasing temperature. For the sample studied in this work, the decrease in photoconductivity occurred in two steps at characteristic temperatures T{sub 1} and T{sub 2}. The characteristic temperatures increased with increasing excitation intensity, very similar to the photoluminescence (PL) behavior. The steps in photoconductivity at about 100 K and 200 K are attributed to drop in the concentration of free electrons due to the thermal emission of holes from a shallow acceptor and the Zn{sub Ga} acceptor, respectively, to the valence band and their recombination with electrons via nonradiative centers. This finding supports the model suggested previously and helps to explain other examples of tunable photoconductivity reported in literature.

Reshchikov, Michael A. [Department of Physics, Virginia Commonwealth University, Richmond, VA 23284 (United States)

2014-02-21T23:59:59.000Z

382

Effects of surface grinding conditions on the reciprocating friction and wear behavior of silicon nitride  

SciTech Connect (OSTI)

The relationship between two significantly different surface grinding conditions and the reciprocating ball-on-flat friction and wear behavior of a high-quality, structural silicon nitride material (GS-44) was investigated. The slider materials were silicon nitride NBD 200 and 440C stainless steel. Two machining conditions were selected based on extensive machining and flexural strength test data obtained under the auspices of an international, interlaboratory grinding study. The condition categorized as {open_quotes}low strength{close_quote} grinding used a coarse 80 grit wheel and produced low flexure strength due to machining-induced flaws in the surface. The other condition, regarded as {open_quotes}high strength grinding,{close_quotes} utilized a 320 grit wheel and produced a flexural strength nearly 70% greater. Grinding wheel surface speeds were 35 and 47 m/s. Reciprocating sliding tests were conducted following the procedure described in a newly-published ASTM standard (G- 133) for linearly-reciprocating wear. Tests were performed in directions both parallel and perpendicular to the grinding marks (lay) using a 25 N load, 5 Hz reciprocating frequency, 10 mm stroke length, and 100 m of sliding at room temperature. The effects of sliding direction relative to the lay were more pronounced for stainless steel than for silicon nitride sliders. The wear of stainless steel was less than the wear of the silicon nitride slider materials because of the formation of transfer particles which covered the sharp edges of the silicon nitride grinding grooves and reduced abrasive contact. The wear of the GS-44 material was much greater for the silicon nitride sliders than for the stainless steel sliders. The causes for the effects of surface-grinding severity and sliding direction on friction and wear of GS-44 and its counterface materials are explained.

Blau, P.J.; Martin, R.L.; Zanoria, E.S.

1997-12-31T23:59:59.000Z

383

Polarity determination for MOCVD growth of GaN on Si(111) by convergent beam electron diffraction[Metal Organic Chemical Vapor Deposition  

SciTech Connect (OSTI)

The polarity of laterally epitaxially overgrown (LEO) GaN on Si(111) with an AlN buffer layer grown by MOCVD has been studied by convergent beam electron diffraction (CBED). The LEO GaN was studied by cross-section and plan-view transmission electron microscopy (TEM). The threading dislocation density is less than 10{sup 8} cm{sup {minus}2} and no inversion domains were observed. CBED patterns were obtained at 200 kV for the <1 {bar 1} 00> zone. Simulation was done by many-beam solution with 33 zero-order beams. The comparison of experimental CBED patterns and simulated patterns indicates that the polarity of GaN on Si(111) is Ga face.

Zhao, L.; Marchand, H.; Fini, P.; Denbaars, S.P.; Mishra, U.K.; Speck, J.S.

2000-07-01T23:59:59.000Z

384

Alternative Liquid Fuel Effects on Cooled Silicon Nitride Marine Gas Turbine Airfoils  

SciTech Connect (OSTI)

With prior support from the Office of Naval Research, DARPA, and U.S. Department of Energy, United Technologies is developing and engine environment testing what we believe to be the first internally cooled silicon nitride ceramic turbine vane in the United States. The vanes are being developed for the FT8, an aeroderivative stationary/marine gas turbine. The current effort resulted in further manufacturing and development and prototyping by two U.S. based gas turbine grade silicon nitride component manufacturers, preliminary development of both alumina, and YTRIA based environmental barrier coatings (EBC's) and testing or ceramic vanes with an EBC coating.

Holowczak, J.

2002-03-01T23:59:59.000Z

385

Proton exchange membrane fuel cells with chromium nitride nanocrystals as electrocatalysts  

Science Journals Connector (OSTI)

Polymer electrolyte membrane fuel cells(PEMFCs) are energy conversion devices that produce electricity from a supply of fuel such as hydrogen. One of the major challenges in achieving efficient energy conversion is the development of cost-effective materials that can act as electrocatalysts for PEMFCs. In this letter we demonstrate that instead of conventional noble metals such as platinum chromium nitride nanocrystals of fcc structure exhibit attractive catalytic activity for PEMFCs. Device testing indicates good stability of nitride nanocrystals in low temperature fuel cell operational environment.

Hexiang Zhong; Xiaobo Chen; Huamin Zhang; Meiri Wang; Samuel S. Mao

2007-01-01T23:59:59.000Z

386

Efficient boron nitride nanotube formation via combined laser-gas flow levitation  

DOE Patents [OSTI]

A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z.

Whitney, R. Roy; Jordan, Kevin; Smith, Michael

2014-03-18T23:59:59.000Z

387

Cubic boron nitride: a new prospective material for ultracold neutron application  

E-Print Network [OSTI]

For the first time, the neutron optical wall-potential of natural cubic boron nitride (cBN) was measured at the ultracold neutron (UCN) source of the research reactor TRIGA Mainz using the time-of-flight method (TOF). The samples investigated had a wall-potential of (305 +/- 15) neV. This value is in good agreement with the result extracted from neutron reflectometry data and theoretical expectations. Because of its high critical velocity for UCN and its good dielectric characteristics, cubic boron nitride coatings (isotopically enriched) will be useful for a number of applications in UCN experiments.

Sobolev, Yu; Borisov, Yu; Daum, M; Fresne, N du; Goeltl, L; Hampel, G; Heil, W; Knecht, A; Keunecke, M; Kratz, J V; Lang, T; Meister, M; Plonka-Spehr, Ch; Pokotilovski, Yu; Reichert, P; Schmidt, U; Krist, Th; Wiehl, N; Zenner, J

2009-01-01T23:59:59.000Z

388

The thermal conductivity of silicon nitride with molybdenum disilicide additions  

SciTech Connect (OSTI)

Room-temperature thermal conductivity has been measured for a series of silicon nitride (Si{sub 3}N{sub 4}) matrix composites with molybdenum disilicide (MoSi{sub 2}) additions of 2, 5 10, 25 and 50 wt. %. Included in these measurements were a pure MoSi{sub 2} sample and a Si{sub 3}N{sub 4} sample containing only sintering aids. Aluminum oxide (Al{sub 2}O{sub 3}) and yttrium oxide (Y{sub 2}O{sub 3}) were added as the sintering aids, at approximately 6 and 2 respectively. When the amount of MoSi{sub 2} was increased to greater than 10 wt. %, the amount of the sintering aids necessary to densify the composite was decreased. No sintering aids were added to the pure MoSi{sub 2} sample. Thermal conductivities of the Si{sub 3}N{sub 4} sample without MoSi{sub 2} and the pure MoSi{sub 2} sample wee 36 W/m.K and 52 W/m.K respectively, which agree very well with the literature values for similar materials. No statistically significant changes were observed in the thermal conductivity for those samples containing up to 10 wt. % MoSi{sub 2}. However, between 10 and 25 wt. % MoSi{sub 2} there was a dramatic decrease in the thermal conductivity from 37 to 20.9 W/m.K. The thermal conductivity then increased steadily with further additions of MoSi{sub 2} up to 52 W/m.K for the pure MoSi{sub 2} specimen.

Beecher, S.C.; Dinwiddie, R.B.; Abeel, A.M.; Lowden, R.A.

1993-12-31T23:59:59.000Z

389

Evaluation of growth methods for the heteroepitaxy of non-polar (11-20) GaN on sapphire by MOVPE  

E-Print Network [OSTI]

double grating spectrometer equipped with a Peltier-cooled GaAs photomultiplier tube. The spectra were recorded with signal lock-in processing techniques. As the HeCd laser absorption length is ca. 350 nm for 99% absorption in GaN (ignoring any carrier... double grating spectrometer equipped with a Peltier-cooled GaAs photomultiplier tube. The spectra were recorded with signal lock-in processing techniques. As the HeCd laser absorption length is ca. 350 nm for 99% absorption in GaN (ignoring any carrier...

Oehler, F.; Sutherland, D.; Zhu, T.; Emery, R.; Badcock, T. J.; Kappers, M. J.; Humphreys, C. J.; Dawson, P.; Oliver, R. A.

2014-09-16T23:59:59.000Z

390

Highly mismatched crystalline and amorphous GaN(1-x)As(x) alloys in the whole composition range  

SciTech Connect (OSTI)

Alloying is a commonly accepted method to tailor properties of semiconductor materials for specific applications. Only a limited number of semiconductor alloys can be easily synthesized in the full composition range. Such alloys are, in general, formed of component elements that are well matched in terms of ionicity, atom size, and electronegativity. In contrast there is a broad class of potential semiconductor alloys formed of component materials with distinctly different properties. In most instances these mismatched alloys are immiscible under standard growth conditions. Here we report on the properties of GaN1-xAsx, a highly mismatched, immiscible alloy system that was successfully synthesized in the whole composition range using a nonequilibrium low temperature molecular beam epitaxy technique. The alloys are amorphous in the composition range of 0.17GaN to ~;;0.8 eV at x~;;0.85. The reduction in the band gap can be attributed primarily to the downward movement of the conduction band for alloys with x>0.2, and to the upward movement of the valence band for alloys with x<0.2. The unique features of the band structure offer an opportunity of using GaN1-xAsx alloys for various types of solar power conversion devices.

Yu, K. M.; Novikov, S. V.; Broesler, R.; Demchenko, I. N.; Denlinger, J. D.; Liliental-Weber, Z.; Luckert, F.; Martin, R. W.; Walukiewicz, W.; Foxon, C. T.

2009-08-29T23:59:59.000Z

391

K.K. Gan US ATLAS Pixel Upgrade Workshop 1 Results of LHC & SLHC Opto-Link R&D  

E-Print Network [OSTI]

-Hardness of GaAs PIN AOC ULM irradiate PIN with 24 GeV protons at CERN SLHC dosage: 2.6 x 1015 p/cm2 (8.2 x study? Gb/s Responsivity (A/W) GaAs Pre Post ULM 4.25 0.50 0.13 AOC 2.5 0.60 0.19 Optowell 3.125 0.60 0 dosage: AOC(5 & 10 G) have good power #12;K.K. Gan US ATLAS Pixel Upgrade Workshop 8 Opto-Chips 1

Gan, K. K.

392

GaN nanorod light emitting diodes with suspended graphene transparent electrodes grown by rapid chemical vapor deposition  

SciTech Connect (OSTI)

Ordered and dense GaN light emitting nanorods are studied with polycrystalline graphene grown by rapid chemical vapor deposition as suspended transparent electrodes. As the substitute of indium tin oxide, the graphene avoids complex processing to fill up the gaps between nanorods and subsequent surface flattening and offers high conductivity to improve the carrier injection. The as-fabricated devices have 32% improvement in light output power compared to conventional planar GaN-graphene diodes. The suspended graphene remains electrically stable up to 300?°C in air. The graphene can be obtained at low cost and high efficiency, indicating its high potential in future applications.

Xu, Kun; Xu, Chen, E-mail: xuchen58@bjut.edu.cn; Deng, Jun; Zhu, Yanxu; Guo, Weiling; Mao, Mingming; Xun, Meng; Chen, Maoxing; Zheng, Lei [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China)] [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China); Xie, Yiyang [State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083 (China)] [State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing 100083 (China); Sun, Jie, E-mail: jie.sun@chalmers.se [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China) [Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124 (China); Mikroteknologi och Nanovetenskap, Chalmers Tekniska Högskola AB, Göteborg 41296 (Sweden)

2013-11-25T23:59:59.000Z

393

Hands-On Session 6: Monolayer Boron Nitride BerkeleyGW Workshop  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Hands-On Session 6: Monolayer Boron Nitride Hands-On Session 6: Monolayer Boron Nitride BerkeleyGW Workshop 11/23/2013 Diana Qiu Goals: 1. Demonstrate a GW-BSE calculation for a 2D semiconductor 2. Look at the behavior of Īµ -1 00 (q) for a system with a truncated Coulomb interaction 3. Learn how to use BerkeleyGW's visualization tools to look at the exciton wave function Instructions: Please copy the example directory into your scratch directory >> cp -rP /project/projectdirs/m1694/BGW-2013/6-boron_nitride $SCRATCH/ 1-MF ā—¸ Please go the directory ``6-boron_nitride/1-mf/`` ā—¸ Enter each directory in numerical order and follow the instructions in the README files. Some things to note for 2D calculations: ā—¸ The system is in a periodic supercell. Though we will not do so in this calculation, you should always converge the k-grid sampling and amount of vacuum between

394

Growth Mechanisms of Vertically-aligned Carbon, Boron Nitride, and Zinc Oxide Nanotubes  

SciTech Connect (OSTI)

Nanotubes are one-dimensional nanomaterials with all atoms located near the surface. This article provides a brief review on the possible growth mechanisms of a series of inorganic nanotubes, in particular, vertically-aligned (VA) carbon nanotubes (CNTs), boron nitride nanotubes (BNNTs), and ZnO nanotubes (ZnO NTs).

Yap, Yoke Khin [Department of Physics, Michigan Technological University, 118 Fisher Hall, 1400 Townsend Drive, Houghton, MI 49931 (United States)

2009-07-07T23:59:59.000Z

395

Disordered graphene and boron nitride in a microwave tight-binding analogue S. Barkhofen,1  

E-Print Network [OSTI]

Disordered graphene and boron nitride in a microwave tight-binding analogue S. Barkhofen,1 M Sophia-Antipolis, 06108 Nice, France (Dated: December 20, 2012) Experiments on hexagonal graphene of the high flexibility of the discs positions, consequences of the disorder introduced in the graphene

Paris-Sud XI, UniversitƩ de

396

Numerical simulation of the heat transfer in amorphous silicon nitride membrane-based microcalorimeters  

E-Print Network [OSTI]

Numerical simulation of the heat transfer in amorphous silicon nitride membrane July 2003 Numerical simulations of the two-dimensional 2D heat flow in a membrane-based microcalorimeter have been performed. The steady-state isotherms and time-dependent heat flow have been calculated

Hellman, Frances

397

Silicon-doped boron nitride coated fibers in silicon melt infiltrated composites  

DOE Patents [OSTI]

A fiber-reinforced silicon--silicon carbide matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is produced. The invention also provides a method for protecting the reinforcing fibers in the silicon--silicon carbide matrix composites by coating the fibers with a silicon-doped boron nitride coating.

Corman, Gregory Scot (Ballston Lake, NY); Luthra, Krishan Lal (Schenectady, NY)

1999-01-01T23:59:59.000Z

398

Silicon-doped boron nitride coated fibers in silicon melt infiltrated composites  

DOE Patents [OSTI]

A fiber-reinforced silicon-silicon carbide matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is produced. The invention also provides a method for protecting the reinforcing fibers in the silicon-silicon carbide matrix composites by coating the fibers with a silicon-doped boron nitride coating.

Corman, Gregory Scot (Ballston Lake, NY); Luthra, Krishan Lal (Schenectady, NY)

2002-01-01T23:59:59.000Z

399

Method for Improving Mg Doping During Group-III Nitride MOCVD  

DOE Patents [OSTI]

A method for improving Mg doping of Group III-N materials grown by MOCVD preventing condensation in the gas phase or on reactor surfaces of adducts of magnesocene and ammonia by suitably heating reactor surfaces between the location of mixing of the magnesocene and ammonia reactants and the Group III-nitride surface whereon growth is to occur.

Creighton, J. Randall (Albuquerque, NM); Wang, George T. (Albuquerque, NM)

2008-11-11T23:59:59.000Z

400

Formation of Nickel Silicide from Direct-Liquid-Injection Chemical-Vapor-Deposited Nickel Nitride Films  

E-Print Network [OSTI]

. Published April 28, 2010. Metal silicides such as TiSi2 and CoSi2 have been commonly used as the contactsFormation of Nickel Silicide from Direct-Liquid-Injection Chemical-Vapor-Deposited Nickel Nitride as the intermediate for subsequent conversion into nickel silicide NiSi , which is a key material for source, drain

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Graphene field-effect transistors based on boron nitride gate dielectrics Inanc Meric1  

E-Print Network [OSTI]

Graphene field-effect transistors based on boron nitride gate dielectrics Inanc Meric1 , Cory Dean1, 10027 Tel: (212) 854-2529, Fax: (212) 932-9421, Email: shepard@ee.columbia.edu Abstract Graphene field of graphene, as the gate dielectric. The devices ex- hibit mobility values exceeding 10,000 cm2 /V

Shepard, Kenneth

402

Characterization of the nitrogen split interstitial defect in wurtzite aluminum nitride using density functional theory  

SciTech Connect (OSTI)

We carried out Heyd-Scuseria-Ernzerhof hybrid density functional theory plane wave supercell calculations in wurtzite aluminum nitride in order to characterize the geometry, formation energies, transition levels, and hyperfine tensors of the nitrogen split interstitial defect. The calculated hyperfine tensors may provide useful fingerprint of this defect for electron paramagnetic resonance measurement.

Szįllįs, A., E-mail: szallas.attila@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Szįsz, K. [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Institute of Physics, Eötvös University, Pįzmįny Péter sétįny 1/A, H-1117 Budapest (Hungary); Trinh, X. T.; Son, N. T.; Janzén, E. [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Gali, A., E-mail: gali.adam@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki śt 8, H-1111 Budapest (Hungary)

2014-09-21T23:59:59.000Z

403

Tuning the optical properties of dilute nitride site controlled quantum dots  

SciTech Connect (OSTI)

We show that deterministic control of the properties of pyramidal site-controlled quantum dots (QD) could be achieved by exposing the QD layer to nitrogen precursor unsymmetrical dimethylhydrazine (UDMHy). The properties that could be tuned include an expected emission reduction in dilute nitride materials, excitonic pattern (biexciton binding energy) and improved carrier confinement potential symmetry (reduced fine-structure splitting)

Juska, G.; Dimastrodonato, V.; Mereni, L. O.; Gocalinska, A.; Pelucchi, E. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)

2013-12-04T23:59:59.000Z

404

Electronic structure and pairwise interactions in substoichiometric transition metal carbides and nitrides  

E-Print Network [OSTI]

1001 Electronic structure and pairwise interactions in substoichiometric transition metal carbides observations expƩri- mentales. Abstract 2014 In substoichiometric transition metal carbides and nitrides This paper is devoted to the study of the ordering processes in substoichiometric transition metal carbi- des

Paris-Sud XI, UniversitƩ de

405

Compressibilities and phonon spectra of high-hardness transition metal-nitride materials  

SciTech Connect (OSTI)

We report compressibilities measured by synchrotron X-ray diffraction and phonon spectra from Raman scattering at high pressure in the diamond anvil cell (DAC) for cubic transition metal nitrides TiN{sub 1-x}, {gamma}-Mo{sub 2}N and VN{sub x}. The high-hardness metal nitride compounds have large values of the bulk modulus. B1-structured nitrides normally have no allowed first-order Raman spectra. However, they exhibit broad bands that reflect the vibrational density of states g({omega}) associated with breakdown of q=0 selection rules because of the presence of N{sup 3-} vacancies on anion sites. Peaks in g({omega}) at low frequency are identified with the longitudinal and transverse acoustic (TA) branches. The maximum in the TA band is correlated with the superconducting transition temperature in these materials (T{sub c}). In situ Raman scattering measurements in the DAC thus permit predictions of the T{sub c} variation with pressure for cubic nitrides and isostructural carbide materials.

Shebanova, O.; Soignard, E.; Mcmillan, P.F. (ASU); (UCL)

2010-01-20T23:59:59.000Z

406

ORDER AND DISORDER IN CARBIDES AND NITRIDES Ch. H. DE NOVION and V. MAURICE  

E-Print Network [OSTI]

transition metals, rare earths and actinides react with carbon and nitrogen to form metallic carbides experimental evidence for short and long-range ordering of point defects in metallic transition metal, rareCOMPOUNDS. ORDER AND DISORDER IN CARBIDES AND NITRIDES Ch. H. DE NOVION and V. MAURICE SESI, C

Paris-Sud XI, UniversitƩ de

407

Formation of BN and AlBN during nitridation of sapphire using RF plasma sources[Radiofrequency  

SciTech Connect (OSTI)

Evidence is presented that nitrogen plasma sources utilizing a pyrolytic boron nitride liner may be a significant source of B contamination during growth and processing. Auger electron spectroscopy analysis performed during nitridation of sapphire indicate the resulting layers contain a significant amount of BN. The formation of Al{sub 1{minus}x}B{sub x}N would explain the observation of a lattice constant several percent smaller than AlN as measured by reflection high-energy electron diffraction. The presence of cubic inclusions in layers grown on such a surface may be related to the segregation of BN during the nitridation into its cubic phase.

Ptak, A.J.; Ziemer, K.S.; Holbert, L.J.; Stinespring, C.D.; Myers, T.H.

2000-07-01T23:59:59.000Z

408

Issues associated with the metalorganic chemical vapor deposition of ScGaN and YGaN alloys.  

SciTech Connect (OSTI)

The most energy efficient solid state white light source will likely be a combination of individually efficient red, green, and blue LED. For any multi-color approach to be successful the efficiency of deep green LEDs must be significantly improved. While traditional approaches to improve InGaN materials have yielded incremental success, we proposed a novel approach using group IIIA and IIIB nitride semiconductors to produce efficient green and high wavelength LEDs. To obtain longer wavelength LEDs in the nitrides, we attempted to combine scandium (Sc) and yttrium (Y) with gallium (Ga) to produce ScGaN and YGaN for the quantum well (QW) active regions. Based on linear extrapolation of the proposed bandgaps of ScN (2.15 eV), YN (0.8 eV) and GaN (3.4 eV), we expected that LEDs could be fabricated from the UV (410 nm) to the IR (1600 nm), and therefore cover all visible wavelengths. The growth of these novel alloys potentially provided several advantages over the more traditional InGaN QW regions including: higher growth temperatures more compatible with GaN growth, closer lattice matching to GaN, and reduced phase separation than is commonly observed in InGaN growth. One drawback to using ScGaN and YGaN films as the active regions in LEDs is that little research has been conducted on their growth, specifically, are there metalorganic precursors that are suitable for growth, are the bandgaps direct or indirect, can the materials be grown directly on GaN with a minimal defect formation, as well as other issues related to growth. The major impediment to the growth of ScGaN and YGaN alloys was the low volatility of metalorganic precursors. Despite this impediment some progress was made in incorporation of Sc and Y into GaN which is detailed in this report. Primarily, we were able to incorporate up to 5 x 10{sup 18} cm{sup -3} Y atoms into a GaN film, which are far below the alloy concentrations needed to evaluate the YGaN optical properties. After a no-cost extension was granted on this program, an additional more 'liquid-like' Sc precursor was evaluated and the nitridation of Sc metals on GaN were investigated. Using the Sc precursor, dopant level quantities of Sc were incorporated into GaN, thereby concluding the growth of ScGaN and YGaN films. Our remaining time during the no-cost extension was focused on pulsed laser deposition of Sc metal films on GaN, followed by nitridation in the MOCVD reactor to form ScN. Finally, GaN films were deposited on the ScN thin films in order to study possible GaN dislocation reduction.

Koleske, Daniel David; Knapp, James Arthur; Lee, Stephen Roger; Crawford, Mary Hagerott; Creighton, James Randall; Cross, Karen Charlene; Thaler, Gerald

2009-07-01T23:59:59.000Z

409

Chemical vapor deposition of refractory ternary nitrides for advanced diffusion barriers  

SciTech Connect (OSTI)

Refractory ternary nitride films for diffusion barriers in microelectronics have been grown using chemical vapor deposition. Thin films of titanium-silicon-nitride, tungsten-boron-nitride, and tungsten-silicon-nitride of various compositions have been deposited on 150 mm Si wafers. The microstructure of the films are either fully amorphous for the tungsten based films, or nauocrystalline TiN in an amorphous matrix for titanium-silicon-nitride. All films exhibit step coverages suitable for use in future microelectronics generations. Selected films have been tested as diffusion barriers between copper and silicon, and generally perform extremely weH. These fiIms are promising candidates for advanced diffusion barriers for microelectronics applications. The manufacturing of silicon wafers into integrated circuits uses many different process and materials. The manufacturing process is usually divided into two parts: the front end of line (FEOL) and the back end of line (BEOL). In the FEOL the individual transistors that are the heart of an integrated circuit are made on the silicon wafer. The responsibility of the BEOL is to wire all the transistors together to make a complete circuit. The transistors are fabricated in the silicon itself. The wiring is made out of metal, currently aluminum and tungsten, insulated by silicon dioxide, see Figure 1. Unfortunately, silicon will diffuse into aluminum, causing aluminum spiking of junctions, killing transistors. Similarly, during chemical vapor deposition (CVD) of tungsten from ~fj, the reactivity of the fluorine can cause "worn-holes" in the silicon, also destroying transistors. The solution to these problems is a so-called diffusion barrier, which will allow current to pass from the transistors to the wiring, but will prevent reactions between silicon and the metal.

Custer, Jonathan S.; Fleming, James G.; Roherty-Osmun, Elizabeth; Smith, Paul Martin

1998-09-22T23:59:59.000Z

410

Nanostructure formation during ion assisted growth of GaN by molecular beam epitaxy Bentao Cui and P.I. Cohen  

E-Print Network [OSTI]

Nanostructure formation during ion assisted growth of GaN by molecular beam epitaxy Bentao Cui and P.I. Cohen Department of Electrical and Computer Engineering and Department of Chemical Engineering Prairie, MN 55344 (Dated: March 4, 2005) Ion beam assisted molecular beam epitaxy was used to grow Ga

Cohen, Philip I.

411

Zone-boundary phonons in hexagonal and cubic GaN H. Siegle, G. Kaczmarczyk, L. Filippidis, A. P. Litvinchuk, A. Hoffmann, and C. Thomsen  

E-Print Network [OSTI]

quality are not yet available for neutron-scattering studies we performed second-order Raman-scattering results of second-order Raman-scattering experiments on hexagonal and cubic GaN covering the acoustic and the optical overtone spectral region. Based on a comparison of the experimental scattering data

Nabben, Reinhard

412

Growth of GaN on SiC(0001) by Molecular Beam Epitaxy C. D. LEE (a), ASHUTOSH SAGAR (a), R. M. FEENSTRA  

E-Print Network [OSTI]

]. Silicon carbide has a much better lattice match to GaN (3.4%), and has gained in popularity in recent years as a substrate for both molecular beam epitaxy (MBE) and metal-organic vapor phase epitaxy of Ga where a transition between streaky and spotty behavior occurs in the reflection high energy electron

Feenstra, Randall

413

Boron nitride nanotubes as novel sorbent for solid-phase microextraction of polycyclic aromatic hydrocarbons in environmental water samples  

Science Journals Connector (OSTI)

Boron nitride nanotube (BNNT) is a novel material that shows potential ability in capturing organic pollutants. In this study, BNNTs fixed on a stainless steel fiber by a sol–gel technique were used as sorbent fo...

Meizhen Fu; Hanzhu Xing; Xiangfeng Chen…

2014-09-01T23:59:59.000Z

414

An experiment to test the viability of a gallium-arsenide cathode in a SRF electron gun  

SciTech Connect (OSTI)

Strained gallium arsenide cathodes are used in electron guns for the production of polarized electrons. In order to have a sufficient quantum efficiency lifetime of the cathode the vacuum in the gun must be 10{sup -11} Torr or better, so that the cathode is not destroyed by ion back bombardment or through contamination with residual gases. All successful polarized guns are DC guns, because such vacuum levels can not be obtained in normal conducting RF guns. A superconductive RF gun may provide a sufficient vacuum level due to cryo-pumping of the cavity walls. We report on the progress of our experiment to test such a gun with normal GaAs-Cs crystals.

Kewisch,J.; Ben-Zvi, I.; Rao, T.; Burrill, A.; Pate, D.; Wu, Q.; Todd, R.; Wang, E.; Bluem, H.; Holmes, D.; Schultheiss, T.

2009-05-04T23:59:59.000Z

415

Surface reactivity and oxygen migration in amorphous indium-gallium-zinc oxide films annealed in humid atmosphere  

SciTech Connect (OSTI)

An isotope tracer study, i.e., {sup 18}O/{sup 16}O exchange using {sup 18}O{sub 2} and H{sub 2}{sup 18}O, was performed to determine how post-deposition annealing (PDA) affected surface reactivity and oxygen diffusivity of amorphous indium–gallium–zinc oxide (a-IGZO) films. The oxygen tracer diffusivity was very high in the bulk even at low temperatures, e.g., 200?°C, regardless of PDA and exchange conditions. In contrast, the isotope exchange rate, dominated by surface reactivity, was much lower for {sup 18}O{sub 2} than for H{sub 2}{sup 18}O. PDA in a humid atmosphere at 400?°C further suppressed the reactivity of O{sub 2} at the a-IGZO film surface, which is attributable to –OH-terminated surface formation.

Watanabe, Ken, E-mail: Watanabe.Ken@nims.go.jp [International Center for Young Scientists (ICYS-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)] [International Center for Young Scientists (ICYS-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan); Lee, Dong-Hee [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan) [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Sakaguchi, Isao; Haneda, Hajime [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan)] [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Nomura, Kenji [Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan)] [Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Kamiya, Toshio [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan) [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Materials Research Center for Element Strategy (MCES), Mailbox S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Hosono, Hideo [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan) [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Materials Research Center for Element Strategy (MCES), Mailbox S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Ohashi, Naoki, E-mail: Ohashi.Naoki@nims.go.jp [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan) [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Materials Research Center for Element Strategy (MCES), Mailbox S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan)

2013-11-11T23:59:59.000Z

416

IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 51, NO. 2, FEBRUARY 2003 643 High Linearity and High Efficiency of Class-B Power  

E-Print Network [OSTI]

Identifier 10.1109/TMTT.2002.807682 The galliumĀ­nitride material system is a leading contender for microwave

Rodwell, Mark J. W.

417

MRS Online Publications Page 1 of 10 http://www.mrs.org/publications/epubs/proceedings/fall2002/l/ 07/22/03  

E-Print Network [OSTI]

.C. Chen, D.B. Fenner, T.D. Moustakas, and George Chu Growth of Oriented Gallium Nitride Films on Amorphous

Wetzel, Christian M.

418

Characteristics of trap-filled gallium arsenide photoconductive switches used in high gain pulsed power applications  

SciTech Connect (OSTI)

The electrical properties of semi-insulating (SI) Gallium Arsenide (GaAs) have been investigated for some time, particularly for its application as a substrate in microelectronics. Of late this material has found a variety of applications other than as an isolation region between devices, or the substrate of an active device. High resistivity SI GaAs is increasingly being used in charged particle detectors and photoconductive semiconductor switches (PCSS). PCSS made from these materials operating in both the linear and non-linear modes have applications such as firing sets, as drivers for lasers, and in high impedance, low current Q-switches or Pockels cells. In the non-linear mode, it has also been used in a system to generate Ultra-Wideband (UWB) High Power Microwaves (HPM). The choice of GaAs over silicon offers the advantage that its material properties allow for fast, repetitive switching action. Furthermore photoconductive switches have advantages over conventional switches such as improved jitter, better impedance matching, compact size, and in some cases, lower laser energy requirement for switching action. The rise time of the PCSS is an important parameter that affects the maximum energy transferred to the load and it depends, in addition to other parameters, on the bias or the average field across the switch. High field operation has been an important goal in PCSS research. Due to surface flashover or premature material breakdown at higher voltages, most PCSS, especially those used in high power operation, need to operate well below the inherent breakdown voltage of the material. The lifetime or the total number of switching operations before breakdown, is another important switch parameter that needs to be considered for operation at high bias conditions. A lifetime of {approximately} 10{sup 4} shots has been reported for PCSS's used in UWB-HPM generation [5], while it has exceeded 10{sup 8} shots for electro-optic drivers. Much effort is currently being channeled in the study related to improvements of these two parameters high bias operation and lifetime improvement for switches used in pulsed power applications. The contact material and profiles are another important area of study. Although these problems are being pursued through the incorporation of different contact materials and introducing doping near contacts, it is important that the switch properties and the conduction mechanism in these switches be well understood such that the basic nature of the problems can be properly addressed. In this paper the authors report on these two basic issues related to the device operation, i.e., mechanisms for increasing the hold-off characteristics through neutron irradiation, and the analysis of transport processes at varying field conditions in trap dominated SI GaAs in order to identify the breakdown mechanism during device operation. It is expected that this study would result in a better understanding of photoconductive switches, specifically those used in high power operation.

ISLAM,N.E.; SCHAMILOGLU,E.; MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; JOSHI,R.P.

2000-05-30T23:59:59.000Z

419

spe438-20 page 1 Garrison, N.J., Busby, C.J., Gans, P.B., Putirka, K., and Wagner, D.L., 2008, A mantle plume beneath California? The mid-Miocene Lovejoy flood basalt, northern  

E-Print Network [OSTI]

-Miocene Lovejoy flood basalt, northern California Noah J. Garrison Cathy J. Busby Phillip B. Gans Department the eastern Snake River Plain toward the Yellowstone caldera (Armstrong et al., 1975; Rodgers et al., 1990

Busby, Cathy

420

Characterization of Chemically Vapor Deposited Silicon Nitride Films from Disilane and Ammonia  

Science Journals Connector (OSTI)

Amorphous silicon nitride films a:SiNx were prepared by low pressure chemical vapor deposition (LPCVD) from disilane ( Si2H6) and ammonia ( NH3). Most of the depositions were performed at 600° C with various NH3/Si2H6 gas ratios ranging from 4 to 50. Different deposits with composition (x= N/Si) ranging from silicon-rich to stoichiometric silicon nitride were characterized by means of infrared spectroscopy (FTIR), ellipsometry, electron energy loss spectroscopy (EELS), and their structure analysed by transmission electron microscopy (TEM). Transmission infrared measurements showed low hydrogen content (x= N/Si) and density of the films were correlated with their refractive index and discussed.

Redhouane Henda; Larbi Laanab; Emmanuel Scheid; Robert Fourmeaux

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Ternary silicon germanium nitrides: A class of tunable band gap materials  

Science Journals Connector (OSTI)

Ternary silicon germanium nitrides with compositions of both Si1?xGexN and (Si1?xGex)3N4 are predicted to have a band gap that decreases as the germanium:silicon ratio increases. The band gap is indirect for the silicon-rich compounds but becomes direct as the germanium content increases, due to greater mixing of s and p states in the conduction band. This effect of band gap tunability has recently been reported for (Si1?xGex)3N4 in the spinel structure [Boyko et al., Phys. Rev. B 81, 155207 (2010)]. Our results suggest that this is a more general effect and that ternary group-14 nitrides should form a class of semiconducting materials for which the band gap can be tuned by controlling the composition.

Judy N. Hart; Neil L. Allan; Frederik Claeyssens

2011-12-27T23:59:59.000Z

422

Phase transformations of nano-sized cubic boron nitride to white graphene and white graphite  

SciTech Connect (OSTI)

We report quantum-mechanical investigations that predict the formation of white graphene and nano-sized white graphite from the first-order phase transformations of nano-sized boron nitride thin-films. The phase transformations from the nano-sized diamond-like structure, when the thickness d?>?1.4?nm, to the energetically more stable nano-sized white graphite involve low activation energies of less than 1.0?eV. On the other hand, the diamond-like structure transforms spontaneously to white graphite when d???1.4?nm. In particular, the two-dimensional structure with single-layer boron nitride, the so-called white graphene, could be formed as a result of such transformation.

Dang, Hongli; Liu, Yingdi; Xue, Wenhua; Anderson, Ryan S.; Sewell, Cody R. [Department of Physics and Engineering Physics, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Xue, Sha; Crunkleton, Daniel W. [Department of Chemical Engineering, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Institute of Alternate Energy, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Shen, Yaogen [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon (Hong Kong); Wang, Sanwu, E-mail: sanwu-wang@utulsa.edu [Department of Physics and Engineering Physics, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Institute of Alternate Energy, The University of Tulsa, Tulsa, Oklahoma 74104 (United States)

2014-03-03T23:59:59.000Z

423

Pulsed-ion-beam nitriding and smoothing of titanium surface in a vacuum  

SciTech Connect (OSTI)

Both nitriding and smoothing of titanium have been achieved under irradiation of intense pulsed ion beam in a vacuum of 2x10{sup -2} Pa. Applying a screening method, we find that medium ion-beam intensity and multi-shot irradiation are effective for the processing, where repetitive surface melting with limited ablation favored Ti nitride formation as well as surface smoothing. The present results demonstrate that ambient gas atoms/molecules can be efficiently incorporated in metal matrices to form compounds under the ion-beam irradiation. The finding is of great significance for extending application scope of the ion-beam technique in materials research and processing, combined with the recent success in introducing ambient gas into the processing chamber.

Zhu, X.P.; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi; Lei, M.K. [Extreme Energy-Density Research Institute, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Surface Engineering Laboratory, Department of Materials Engineering, Dalian University of Technology, Dalian 116024 (China)

2005-08-29T23:59:59.000Z

424

Nondestructive evaluation of silicon-nitride ceramic valves from engine duration test.  

SciTech Connect (OSTI)

In this study, we investigated impact and wear damage in silicon-nitride ceramic valves that were subjected to an engine duration test in a natural-gas engine. A high-speed automated laser-scattering system was developed for the nondestructive evaluation (NDE) of 10 SN235P silicon-nitride valves. The NDE system scans the entire valve surface and generates a two-dimensional scattering image that is used to identify location, size and relative severity of subsurface damage in the valves. NED imaging data were obtained at before and at 100 and 500 hours of the engine duration test. The NDE data were analyzed and compared with surface photomicrographs. Wear damage was found in the impact surface of all valves, expecially for exhaust valves. However, the NDE examination did not detect subsurface damage such as cracks or spalls in these engine-tested valves.

Sun, J. G.; Trethewey, J. S.; Vanderspiegle, N. N.; Jensen, J. A.; Nuclear Engineering Division; Caterpillar, Inc.

2008-01-01T23:59:59.000Z

425

Effects of plasma-deposited silicon nitride passivation on the radiation hardness of CMOS integrated circuits  

SciTech Connect (OSTI)

The use of plasma-deposited silicon nitride as a final passivation over metal-gate CMOS integrated circuits degrades the radiation hardness of these devices. The hardness degradation is manifested by increased radiation-induced threshold voltage shifts caused principally by the charging of new interface states and, to a lesser extent, by the trapping of holes created upon exposure to ionizing radiation. The threshold voltage shifts are a strong function of the deposition temperature, and show very little dependence on thickness for films deposited at 300/sup 0/C. There is some correlation between the threshold voltage shifts and the hydrogen content of the PECVD silicon nitride films used as the final passivation layer as a function of deposition temperature. The mechanism by which the hydrogen contained in these films may react with the Si/SiO/sub 2/ interface is not clear at this point.

Clement, J. J.

1980-01-01T23:59:59.000Z

426

Soliton mechanism of the uranium nitride microdynamics and heat conductivity at high temperatures  

SciTech Connect (OSTI)

The microdynamics of soliton waves and localized modes of nonlinear acoustic and optical oscillations in uranium nitride has been investigated. It is shown that, upon heating, the energies of solitons in the gap between the optical and acoustic phonon bands increase, while the energies of local modes decrease. The experimentally observed quasi-resonance features, which are shifted in the gap with a change in temperature, can be manifestations of the revealed soliton waves and local modes. The microdynamics of uranium nitride heat conductivity with the stochastic generation of the observed solitons and local modes at remote energy absorption have been investigated. The temperature dependence of the heat conductivity coefficient has been determined from the temperature gradient and energy flux within the standard approach (which is to be generalized).

Semenov, V. A.; Dubovsky, O. A., E-mail: dubov@ippe.ru; Orlov, A. V. [State Scientific Center of the Russian Federation Leipunsky Institute for Physics and Power Engineering (Russian Federation)

2011-12-15T23:59:59.000Z

427

Heteroepitaxy of group IV-VI nitrides by atomic layer deposition  

SciTech Connect (OSTI)

Heteroepitaxial growth of selected group IV-VI nitrides on various orientations of sapphire (?-Al{sub 2}O{sub 3}) is demonstrated using atomic layer deposition. High quality, epitaxial films are produced at significantly lower temperatures than required by conventional deposition methods. Characterization of electrical and superconducting properties of epitaxial films reveals a reduced room temperature resistivity and increased residual resistance ratio for films deposited on sapphire compared to polycrystalline samples deposited concurrently on fused quartz substrates.

Klug, Jeffrey A., E-mail: jklug@anl.gov; Groll, Nickolas R.; Pellin, Michael J.; Proslier, Thomas, E-mail: prolier@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Becker, Nicholas G.; Cao, Chaoyue; Zasadzinski, John F. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Weimer, Matthew S. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616 (United States)

2013-11-18T23:59:59.000Z

428

Ab initio study of phase transition of boron nitride between zinc-blende and rhombohedral structures  

SciTech Connect (OSTI)

Boron nitride has polymorphs such as zinc-blende (c-BN), wurtzite (w-BN), rhombohedral (r-BN), and graphite-like (h-BN) forms. We simulate the direct conversion of r-BN to c-BN through electronic excitation. In our calculation, the conversion is made possible by increasing the hole concentration to over 0.06/atom. This conversion should be experimentally possible by hole-doping via an electric double layer transistor (EDLT) or capacitor.

Nishida, S.; Funashima, H.; Sato, K.; Katayama-Yoshida, H. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

2013-12-04T23:59:59.000Z

429

Integrated rig for the production of boron nitride nanotubes via the pressurized vapor-condenser method  

DOE Patents [OSTI]

An integrated production apparatus for production of boron nitride nanotubes via the pressure vapor-condenser method. The apparatus comprises: a pressurized reaction chamber containing a continuously fed boron containing target having a boron target tip, a source of pressurized nitrogen and a moving belt condenser apparatus; a hutch chamber proximate the pressurized reaction chamber containing a target feed system and a laser beam and optics.

Smith, Michael W; Jordan, Kevin C

2014-03-25T23:59:59.000Z

430

Quantifying the Solubility of Boron Nitride Nanotubes and Sheets with Static Light Scattering and Refractometry  

SciTech Connect (OSTI)

The dissolution of nanoparticles, particularly those containing boron, is an important area of interest for polymer nanocomposite formation and material development. In this work, the solubility of boron nitride nanotubes (BNNT), functionalized boron nitride nanotubes (FBNNT), and boron nitride sheets (BNZG) is quantified in toluene and THF with static light scattering, refractometry, UV vis spectroscopy, and physical observations. UV vis spectroscopy provides a method to determine the concentration and solubility limits of the solutions tested. Using light scattering, the second virial coefficient, A2, is determined and used to calculate , the solute solvent interaction parameter. The Hildebrand solubility parameter, , is then extracted from this data using the Hildebrand Scatchard Solution Theory. A list of potential good solvents based on the estimated value is provided for each nanoparticle. Single-walled carbon nanotubes (SWNTs) and prepolymers (EN4 and EN8) used to synthesize polyurethanes were also tested, because the published and molar attraction constants of these materials provided a selfconsistent check. The dn/dc of SWNTs and boron-containing particles was measured for the first time in this work. A solvent screen for BN-ZG provides additional information that supports the obtained and . Three systems were found to have values below 0.5 and were thermodynamically soluble: BNNT in THF, EN8 in THF, and EN8 in toluene.

Mutz, M [The University of Tennessee; Eastwood, Eric Allen [ORNL; Dadmun, Mark D [ORNL

2013-01-01T23:59:59.000Z

431

An electrochemical method suitable for preparing nine metal-nitride powders  

SciTech Connect (OSTI)

We present an electrochemical method that is suitable for the preparation of metal-nitride ceramic materials that is both simple and general. We begin with a single-compartment electrochemical cell containing suitable metal (M) anodes and cathodes (M=Al, Mo, Nb, Ni, Ti, V, W, Zn, or Zr) and a NH{sub 3}/NH{sub 4}X (X=Br or Cl) electrolyte solution. Application of a sufficiently high voltage results in oxidation and dissolution of M to M{sup n+} at the anode and reduction of NH{sub 3} to NH{sub 2}- at the cathode. When M=Al, this results in formation of an insoluble inorganic polymer, which can subsequently be calcined above 600{degrees}C to yield phase-pure AlN. For some of the other metals, a simple ammoniated metal ion is formed at the anode, but calcination of this material also leads to the corresponding metal nitride. The phases and morphologies of the powders depends strongly on the calcining conditions. The important point is that this method is general for the preparation of metal-nitride powders even though the pathway that leads to the powders is metal-dependent. This talk will focus primarily on the preparation of AlN, which is an important packaging material for the electronics industry, and NbN, which is a superconductor (T{sub c}{approximately}17 K) with important technological applications.

Wade, T.; Crooks, R.M. [Texas A& M Univ., College Station, TX (United States)

1995-12-31T23:59:59.000Z

432

Microsoft Word - 25A2445 Continued  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

This ARPA-E program plans to address the vast energy loss and consumption associated with conventional lighting by developing a new This ARPA-E program plans to address the vast energy loss and consumption associated with conventional lighting by developing a new route to large, high-quality, single crystals of gallium nitride. These crystals will serve as substrates for LEDs offering high-efficiency lighting. Around 8% of the energy consumption in the U.S. is from lighting, and by 2025, the U.S. could consume as much as 1,000 TWh per year. In addition, conventional light sources can account for more than 25% of a building's energy demands in the forms of direct energy for lighting, waste heat from the lights, and higher HVAC costs due to the waste heat. With its more efficient light production and minimal waste heat, gallium-nitride (GaN) Solid- State Lighting (SSL) technology has the potential to reduce energy consumption by

433

On the influence of solution density on the formation of macroscopic defects in the liquid phase epitaxy of GaN  

Science Journals Connector (OSTI)

This paper reports on a new simple method for avoiding particle-induced macroscopic defects using the liquid phase epitaxy (LPE) of GaN as an example. In a series of growth experiments by LPE of GaN it is demonstrated that the number of particle-induced macrodefects in the epitaxial layers correlates strongly and reproducibly with the density of the solution. In solutions with a density higher than that of the deleterious particles, the particles float on the solution and hence are hindered to get into contact with the seed, which is placed at the bottom of the crucible. Consequently, so-called depressions — a typical particle-induced defect in GaN–LPE layers — are avoided. The principle of avoiding the formation of macroscopic defects originating from particles by adapting the density of the solution (density criterion) should be generally applicable to solution growth processes, regardless of the material system.

S. Hussy; P. Berwian; E. Meissner; J. Friedrich; G. Müller

2008-01-01T23:59:59.000Z

434

Confirmation of intrinsic electron gap states at nonpolar GaN(1-100) surfaces combining photoelectron and surface optical spectroscopy  

SciTech Connect (OSTI)

The electronic structure of GaN(1–100) surfaces is investigated in-situ by photoelectron spectroscopy (PES) and reflection anisotropy spectroscopy (RAS). Occupied surface states 3.1?eV below the Fermi energy are observed by PES, accompanied by surface optical transitions found in RAS around 3.3?eV, i.e., below the bulk band gap. These results indicate that the GaN(1–100) surface band gap is smaller than the bulk one due to the existence of intra-gap states, in agreement with density functional theory calculations. Furthermore, the experiments demonstrate that RAS can be applied for optical surface studies of anisotropic crystals.

Himmerlich, M., E-mail: marcel.himmerlich@tu-ilmenau.de; Eisenhardt, A.; Shokhovets, S.; Krischok, S. [Institut für Physik and Institut für Mikro- und Nanotechnologien, TU Ilmenau, PF 100565, 98684 Ilmenau (Germany); Räthel, J.; Speiser, E.; Neumann, M. D.; Navarro-Quezada, A.; Esser, N. [Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Albert-Einstein-Strasse 9, 12489 Berlin (Germany)

2014-04-28T23:59:59.000Z

435

Power mixture and green body for producing silicon nitride base articles of high fracture toughness and strength  

DOE Patents [OSTI]

A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength are disclosed. The powder mixture includes (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12m[sup 2]g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder. No Drawings

Huckabee, M.L.; Buljan, S.T.; Neil, J.T.

1991-09-17T23:59:59.000Z

436

Page not found | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

21 - 13730 of 26,764 results. 21 - 13730 of 26,764 results. Download CX-010974: Categorical Exclusion Determination Advanced Low-Cost Silicon Carbide (SiC) and Gallium Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction... CX(s) Applied: B3.6 Date: 09/16/2013 Location(s): Arkansas Offices(s): National Energy Technology Laboratory http://energy.gov/nepa/downloads/cx-010974-categorical-exclusion-determination Download CX-010975: Categorical Exclusion Determination Advanced Climate Control and Cabin Preconditioning using Zonal Distribution, Advanced Heat Pump... CX(s) Applied: B3.6, B5.1 Date: 09/16/2013 Location(s): Michigan Offices(s): National Energy Technology Laboratory http://energy.gov/nepa/downloads/cx-010975-categorical-exclusion-determination Download CX-010976: Categorical Exclusion Determination

437

Cree Inc | Open Energy Information  

Open Energy Info (EERE)

Cree Inc Cree Inc Jump to: navigation, search Name Cree Inc Place Durham, North Carolina Zip 27703 Product Cree develops and manufactures semiconductor materials and devices based on silicon carbide (SiC), gallium nitride (GaN), silicon (Si) and related compounds. Coordinates 45.396265Ā°, -122.755099Ā° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":45.396265,"lon":-122.755099,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

438

U.S. DEPARTIVmNT OF ENFRGY EERE PROJECT MANAGEMENT CENTER NEP.A DETFmllNATION  

Broader source: Energy.gov (indexed) [DOE]

DEPARTIVmNT OF ENFRGY DEPARTIVmNT OF ENFRGY EERE PROJECT MANAGEMENT CENTER NEP.A DETFmllNATION RECIPIENT:MEMC Electronic Materials, Inc. Page 1 of2 STATE: MO PROJECT TITLE: High Quality, Low Cost Bulk Gallium Nitride (GaN) Substrates Grown by the Electrochemical Solution Growth Method Funding Opportunity Announcement Number DE-FOA-0000560 Procurement Instrument Number NEPA Control Number CID Number DE-EE0005755 GF0-0005755-001 G05755 Based on my r eview of the information concerning the proposed action, as NEPA Compliance Officer (authorized under DOE Order 451.1A), I have made the following determination: CX, EA, EIS APPENDIX AND NUMBER: Description: A9 Information gathering, analysis, and dissemination Information gathering (including, but not limited to, literature surveys, inventories, site visits, and

439

Page not found | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

41 - 8950 of 29,416 results. 41 - 8950 of 29,416 results. Download CX-000845: Categorical Exclusion Determination 25A2445 - Ammonothermal Bulk Gallium Nitride (GaN) Crystal Growth for Energy Efficient Lighting CX(s) Applied: B3.6 Date: 01/15/2010 Location(s): New York Office(s): Advanced Research Projects Agency - Energy http://energy.gov/nepa/downloads/cx-000845-categorical-exclusion-determination Download CX-000839: Categorical Exclusion Determination 25A1089 - Electroville: High-Amperage Energy Storage Device-Energy Storage for the Neighborhood CX(s) Applied: B3.6 Date: 01/15/2010 Location(s): Massachusetts Office(s): Advanced Research Projects Agency - Energy http://energy.gov/nepa/downloads/cx-000839-categorical-exclusion-determination Download CX-000860: Categorical Exclusion Determination

440

Categorical Exclusion (CX) Determinations By Date | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

5, 2010 5, 2010 CX-000839: Categorical Exclusion Determination 25A1089 - Electroville: High-Amperage Energy Storage Device-Energy Storage for the Neighborhood CX(s) Applied: B3.6 Date: 01/15/2010 Location(s): Massachusetts Office(s): Advanced Research Projects Agency - Energy January 15, 2010 CX-000845: Categorical Exclusion Determination 25A2445 - Ammonothermal Bulk Gallium Nitride (GaN) Crystal Growth for Energy Efficient Lighting CX(s) Applied: B3.6 Date: 01/15/2010 Location(s): New York Office(s): Advanced Research Projects Agency - Energy January 15, 2010 CX-000852: Categorical Exclusion Determination 25A4800 - High Energy Permanent Magnets for Hybrid Vehicles and Alternative Energy CX(s) Applied: B3.6 Date: 01/15/2010 Location(s): Delaware Office(s): Advanced Research Projects Agency - Energy

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Categorical Exclusion Determinations: New York | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

January 15, 2010 January 15, 2010 CX-000845: Categorical Exclusion Determination 25A2445 - Ammonothermal Bulk Gallium Nitride (GaN) Crystal Growth for Energy Efficient Lighting CX(s) Applied: B3.6 Date: 01/15/2010 Location(s): New York Office(s): Advanced Research Projects Agency - Energy December 29, 2009 CX-000273: Categorical Exclusion Determination Pressure Sensor and Telemetry Methods for Measurement while Drilling in Geothermal Wells CX(s) Applied: A9, B3.6 Date: 12/29/2009 Location(s): New York Office(s): Energy Efficiency and Renewable Energy, Golden Field Office December 21, 2009 CX-001281: Categorical Exclusion Determination Hire Experts, Lighting Retrofits, and Install Solar Lights CX(s) Applied: A9, B5.1 Date: 12/21/2009 Location(s): Suffolk, New York Office(s): Energy Efficiency and Renewable Energy

442

Stress testing on silicon carbide electronic devices for prognostics and health management.  

SciTech Connect (OSTI)

Power conversion systems for energy storage and other distributed energy resource applications are among the drivers of the important role that power electronics plays in providing reliable electricity. Wide band gap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) will help increase the performance and efficiency of power electronic equipment while condition monitoring (CM) and prognostics and health management (PHM) will increase the operational availability of the equipment and thereby make it more cost effective. Voltage and/or temperature stress testing were performed on a number of SiC devices in order to accelerate failure modes and to identify measureable shifts in electrical characteristics which may provide early indication of those failures. Those shifts can be interpreted and modeled to provide prognostic signatures for use in CM and/or PHM. Such experiments will also lead to a deeper understanding of basic device physics and the degradation mechanisms behind failure.

Kaplar, Robert James; Brock, Reinhard C.; Marinella, Matthew; King, Michael Patrick; Smith, Mark A.; Atcitty, Stanley

2011-01-01T23:59:59.000Z

443

Published in 'Silicon Carbide, III-Nitrides and Related Materials', Year: 1998, pp: 829-832 Periodical: Materials Science Forum Vols. 264-268  

E-Print Network [OSTI]

Published in 'Silicon Carbide, III-Nitrides and Related Materials', Year: 1998, pp: 829@scientific.net Ā© 1998 by Trans Tech Publications Ltd., Switzerland, http://www.ttp.net #12;Published in 'Silicon Carbide Publications Ltd., Switzerland, http://www.ttp.net #12;Published in 'Silicon Carbide, III-Nitrides and Related

Steckl, Andrew J.

444

Published in 'Silicon Carbide, III-Nitrides and Related Materials', Year: 1998, pp: 1149-1152 Periodical: Materials Science Forum Vols. 264-268  

E-Print Network [OSTI]

Published in 'Silicon Carbide, III-Nitrides and Related Materials', Year: 1998, pp: 1149@scientific.net Ā© 1998 by Trans Tech Publications Ltd., Switzerland, http://www.ttp.net #12;Published in 'Silicon Carbide Publications Ltd., Switzerland, http://www.ttp.net #12;Published in 'Silicon Carbide, III-Nitrides and Related

Steckl, Andrew J.

445

The Hessian biased force field for silicon nitride ceramics: Predictions of thermodynamic and mechanical properties for CX-and @S&N4  

E-Print Network [OSTI]

that these calculations provide the first reliable data on such fundamental properties of silicon nitride. This MSXX force in diesel en- gines, industrial heat exchangers, and gas turbines, to name but a few potential applications for engines insulated with silicon nitride, leads to an increased efficiency of these en- gines. However

Goddard III, William A.

446

Process for the production of hydrogen and carbonyl sulfide from hydrogen sulfide and carbon monoxide using a metal boride, nitride, carbide and/or silicide catalyst  

SciTech Connect (OSTI)

Hydrogen and carbonyl sulfide are produced by a process comprising contacting gaseous hydrogen sulfide with gaseous carbon monoxide in the presence of a metal boride, carbide, nitride and/or silicide catalyst, such as titanium carbide, vanadium boride, manganese nitride or molybdenum silicide.

McGuiggan, M.F.; Kuch, P.L.

1984-05-08T23:59:59.000Z

447

Corrugated aluminum nitride energy harvesters for high energy conversion effectiveness This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-Print Network [OSTI]

Corrugated aluminum nitride energy harvesters for high energy conversion effectiveness This article aluminum nitride energy harvesters for high energy conversion effectiveness Ting-Ta Yen1, Taku Hirasawa of micromachining processes with high energy conversion effectiveness. Corrugated cantilever design with a single

Lin, Liwei

448

The near-edge structure in energy-loss spectroscopy: many-electron and magnetic effects in transition metal nitrides and carbides  

E-Print Network [OSTI]

in transition metal nitrides and carbides This article has been downloaded from IOPscience. Please scroll down-loss spectroscopy: many-electron and magnetic effects in transition metal nitrides and carbides A T Paxton, M van energies are systematically overestimated by 4.22 Ā± 0.44 eV in twelve transition metal carbides

Paxton, Anthony T.

449

Sputtering of Si, SiC, InAs, InP, Ge, GaAs, GaSb, and GaN by electrosprayed nanodroplets  

SciTech Connect (OSTI)

This article presents a characterization of the damage caused by energetic beams of electrosprayed nanodroplets striking the surfaces of single-crystal semiconductors including Si, SiC, InAs, InP, Ge, GaAs, GaSb, and GaN. The sputtering yield (number of atoms ejected per projectile's molecule), sputtering rate, and surface roughness are measured as functions of the beam acceleration potential. The maximum values of the sputtering yields range between 1.9 and 2.2 for the technological important but difficult to etch SiC and GaN respectively, and 4.5 for Ge. The maximum sputtering rates for the non-optimized beam flux conditions used in our experiments vary between 409?nm/min for SiC and 2381?nm/min for GaSb. The maximum sputtering rate for GaN is 630?nm/min. Surface roughness increases modestly with acceleration voltage, staying within 2?nm and 20?nm for all beamlet acceleration potentials and materials except Si. At intermediate acceleration potentials, the surface of Si is formed by craters orders of magnitude larger than the projectiles, yielding surface roughness in excess of 60?nm. The effect of projectile dose is studied in the case of Si. This parameter is correlated with the formation of the large craters typical of Si, which suggests that the accumulation of damage following consecutive impacts plays an important role in the interaction between beamlet and target.

Borrajo-Pelaez, Rafael; Grustan-Gutierrez, Enric; Gamero-Castańo, Manuel, E-mail: mgameroc@uci.edu [Department of Mechanical and Aerospace Engineering, University of California, Irvine, California 92697 (United States)

2013-11-14T23:59:59.000Z

450

Laboratory Directed Research and Development (LDRD) on Mono-uranium Nitride Fuel Development for SSTAR and Space Applications  

SciTech Connect (OSTI)

The US National Energy Policy of 2001 advocated the development of advanced fuel and fuel cycle technologies that are cleaner, more efficient, less waste-intensive, and more proliferation resistant. The need for advanced fuel development is emphasized in on-going DOE-supported programs, e.g., Global Nuclear Energy Initiative (GNEI), Advanced Fuel Cycle Initiative (AFCI), and GEN-IV Technology Development. The Directorates of Energy & Environment (E&E) and Chemistry & Material Sciences (C&MS) at Lawrence Livermore National Laboratory (LLNL) are interested in advanced fuel research and manufacturing using its multi-disciplinary capability and facilities to support a design concept of a small, secure, transportable, and autonomous reactor (SSTAR). The E&E and C&MS Directorates co-sponsored this Laboratory Directed Research & Development (LDRD) Project on Mono-Uranium Nitride Fuel Development for SSTAR and Space Applications. In fact, three out of the six GEN-IV reactor concepts consider using the nitride-based fuel, as shown in Table 1. SSTAR is a liquid-metal cooled, fast reactor. It uses nitride fuel in a sealed reactor vessel that could be shipped to the user and returned to the supplier having never been opened in its long operating lifetime. This sealed reactor concept envisions no fuel refueling nor on-site storage of spent fuel, and as a result, can greatly enhance proliferation resistance. However, the requirement for a sealed, long-life core imposes great challenges to research and development of the nitride fuel and its cladding. Cladding is an important interface between the fuel and coolant and a barrier to prevent fission gas release during normal and accidental conditions. In fabricating the nitride fuel rods and assemblies, the cladding material should be selected based on its the coolant-side corrosion properties, the chemical/physical interaction with the nitride fuel, as well as their thermal and neutronic properties. The US NASA space reactor, the SP-100 was designed to use mono-uranium nitride fuel. Although the SP-100 reactor was not commissioned, tens of thousand of nitride fuel pellets were manufactured and lots of them, cladded in Nb-1-Zr had been irradiated in fast test reactors (FFTF and EBR-II) with good irradiation results. The Russian Naval submarines also use nitride fuel with stainless steel cladding (HT-9) in Pb-Bi coolant. Although the operating experience of the Russian submarine is not readily available, such combination of fuel, cladding and coolant has been proposed for a commercial-size liquid-metal cooled fast reactor (BREST-300). Uranium mono-nitride fuel is studied in this LDRD Project due to its favorable properties such as its high actinide density and high thermal conductivity. The thermal conductivity of mono-nitride is 10 times higher than that of oxide (23 W/m-K for UN vs. 2.3 W/m-K for UO{sub 2} at 1000 K) and its melting temperature is much higher than that of metal fuel (2630 C for UN vs. 1132 C for U metal). It also has relatively high actinide density, (13.51 gU/cm{sup 3} in UN vs. 9.66 gU/cm{sup 3} in UO{sub 2}) which is essential for a compact reactor core design. The objective of this LDRD Project is to: (1) Establish a manufacturing capability for uranium-based ceramic nuclear fuel, (2) Develop a computational capability to analyze nuclear fuel performance, (3) Develop a modified UN-based fuel that can support a compact long-life reactor core, and (4) Collaborate with the Nuclear Engineering Department of UC Berkeley on nitride fuel reprocessing and disposal in a geologic repository.

Choi, J; Ebbinghaus, B; Meiers, T; Ahn, J

2006-02-09T23:59:59.000Z

451

A final report for Gallium arsenide P-I-N detectors for high-sensitivity imaging of thermal neutrons  

E-Print Network [OSTI]

This SBIR Phase I developed neutron detectors made FR-om gallium arsenide (GaAs) p-type/ intrinsic/n-type (P-I-N) diodes grown by metalorganic chemical vapor deposition (MOCVD) onto semi-insulating (S1) bulk GaAs wafers. A layer of isotonically enriched boron-10 evaporated onto the FR-ont surface serves to convert incoming neutrons into lithium ions and a 1.47 MeV alpha particle which creates electron-hole pairs that are detected by the GaAs diode. Various thicknesses of ''intrinsic'' (I) undoped GaAs were tested, as was use of a back-surface field (BSF) formed FR-om a layer of Al sub x Ga sub 1 sub - sub x As. Schottky-barrier diodes formed FR-om the same structures without the p+ GaAs top layer were tested as a comparison. After mesa etching and application of contacts, devices were tested in visible light before application of the boron coating. Internal quantum efficiency (IQE) of the best diode near the GaAs bandedge is over 90%. The lowest dark current measured is 1 x 10 sup - sup 1 sup 2 amps at -1 V o...

Vernon, S M

1999-01-01T23:59:59.000Z

452

Electrical Bias as an Alternate Method for Reproducible Measurement of Copper Indium Gallium Diselenide (CIGS) Photovoltaic Modules: Preprint  

SciTech Connect (OSTI)

Light-to-dark metastable changes in thin-film photovoltaic (PV) modules can introduce uncertainty when measuring module performance on indoor flash testing equipment. This study describes a method to stabilize module performance through forward-bias current injection rather than light exposure. Measurements of five pairs of thin-film copper indium gallium diselenide (CIGS) PV modules indicate that forward-bias exposure maintained the PV modules at a stable condition (within 1%) while the unbiased modules degraded in performance by up to 12%. It was additionally found that modules exposed to forward bias exhibited stable performance within about 3% of their long-term outdoor exposed performance. This carrier-injection method provides a way to reduce uncertainty arising from fast transients in thin-film module performance between the time a module is removed from light exposure and when it is measured indoors, effectively simulating continuous light exposure by injecting minority carriers that behave much as photocarriers do. This investigation also provides insight into the initial light-induced transients of thin-film modules upon outdoor deployment.

Deline, C.; Stokes, A.; Silverman, T. J.; Rummel, S.; Jordan, D.; Kurtz, S.

2012-08-01T23:59:59.000Z

453

CO{sub 2} laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements  

SciTech Connect (OSTI)

A dispersion interferometer based on the second-harmonic generation of a carbon dioxide laser in orientation-patterned gallium arsenide has been developed for measuring electron density in plasmas. The interferometer includes two nonlinear optical crystals placed on opposite sides of the plasma. This instrument has been used to measure electron line densities in a pulsed radio-frequency generated argon plasma. A simple phase-extraction technique based on combining measurements from two successive pulses of the plasma has been used. The noise-equivalent line density was measured to be 1.7 × 10{sup 17} m{sup ?2} in a detection bandwidth of 950 kHz. One of the orientation-patterned crystals produced 13 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 13 W of peak power. Two crystals arranged sequentially produced 58 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 37 W of peak power.

Bamford, D. J.; Cummings, E. A.; Panasenko, D. [Physical Sciences Inc., 6652 Owens Drive, Pleasanton, California 94588 (United States)] [Physical Sciences Inc., 6652 Owens Drive, Pleasanton, California 94588 (United States); Fenner, D. B.; Hensley, J. M. [Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States)] [Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States); Boivin, R. L.; Carlstrom, T. N.; Van Zeeland, M. A. [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)] [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)

2013-09-15T23:59:59.000Z

454

III-antimonide/nitride based semiconductors for optoelectronic materials and device studies : LDRD 26518 final report.  

SciTech Connect (OSTI)

The goal of this LDRD was to investigate III-antimonide/nitride based materials for unique semiconductor properties and applications. Previous to this study, lack of basic information concerning these alloys restricted their use in semiconductor devices. Long wavelength emission on GaAs substrates is of critical importance to telecommunication applications for cost reduction and integration into microsystems. Currently InGaAsN, on a GaAs substrate, is being commercially pursued for the important 1.3 micrometer dispersion minima of silica-glass optical fiber; due, in large part, to previous research at Sandia National Laboratories. However, InGaAsN has not shown great promise for 1.55 micrometer emission which is the low-loss window of single mode optical fiber used in transatlantic fiber. Other important applications for the antimonide/nitride based materials include the base junction of an HBT to reduce the operating voltage which is important for wireless communication links, and for improving the efficiency of a multijunction solar cell. We have undertaken the first comprehensive theoretical, experimental and device study of this material with promising results. Theoretical modeling has identified GaAsSbN to be a similar or potentially superior candidate to InGaAsN for long wavelength emission on GaAs. We have confirmed these predictions by producing emission out to 1.66 micrometers and have achieved edge emitting and VCSEL electroluminescence at 1.3 micrometers. We have also done the first study of the transport properties of this material including mobility, electron/hole mass, and exciton reduced mass. This study has increased the understanding of the III-antimonide/nitride materials enough to warrant consideration for all of the target device applications.

Kurtz, Steven Ross; Hargett, Terry W.; Serkland, Darwin Keith; Waldrip, Karen Elizabeth; Modine, Normand Arthur; Klem, John Frederick; Jones, Eric Daniel; Cich, Michael Joseph; Allerman, Andrew Alan; Peake, Gregory Merwin

2003-12-01T23:59:59.000Z

455

Very long single- and few-walled boron nitride nanotubes via the pressurized vapor/condenser method  

SciTech Connect (OSTI)

Boron nitride nanotubes (BNNTs) are desired for their exceptional mechanical, electronic, thermal, structural, textural, optical, and quantum properties. A new method for producing long, small-diameter, single- and few-walled, boron nitride nanotubes (BNNTs) in macroscopic quantities is reported. The pressurized vapor/condenser (PVC) method produces, without catalysts, highly crystalline, very long, small-diameter, BNNTs. Palm-sized, cotton-like masses of BNNT raw material were grown by this technique and spun directly into centimeters-long yarn. Nanotube lengths were observed to be 100 times that of those grown by the most closely related method. Self-assembly and growth models for these long BNNTs are discussed.

Michael W. Smith, Kevin Jordan, Cheol Park, Jae-Woo Kim, Peter Lillehei, Roy Crooks, Joycelyn Harrison

2009-11-01T23:59:59.000Z

456

Rf-plasma synthesis of nanosize silicon carbide and nitride. Final report  

SciTech Connect (OSTI)

A pulsed rf plasma technique is capable of generating ceramic particles of 10 manometer dimension. Experiments using silane/ammonia and trimethylchlorosilane/hydrogen gas mixtures show that both silicon nitride and silicon carbide powders can be synthesized with control of the average particle diameter from 7 to 200 nm. Large size dispersion and much agglomeration appear characteristic of the method, in contrast to results reported by another research group. The as produced powders have a high hydrogen content and are air and moisture sensitive. Post-plasma treatment in a controlled atmosphere at elevated temperature (800{degrees}C) eliminates the hydrogen and stabilizes the powder with respect to oxidation or hydrolysis.

Buss, R.J.

1997-02-01T23:59:59.000Z

457

High performance vertical tunneling diodes using graphene/hexagonal boron nitride/graphene hetero-structure  

SciTech Connect (OSTI)

A tunneling rectifier prepared from vertically stacked two-dimensional (2D) materials composed of chemically doped graphene electrodes and hexagonal boron nitride (h-BN) tunneling barrier was demonstrated. The asymmetric chemical doping to graphene with linear dispersion property induces rectifying behavior effectively, by facilitating Fowler-Nordheim tunneling at high forward biases. It results in excellent diode performances of a hetero-structured graphene/h-BN/graphene tunneling diode, with an asymmetric factor exceeding 1000, a nonlinearity of ?40, and a peak sensitivity of ?12?V{sup ?1}, which are superior to contending metal-insulator-metal diodes, showing great potential for future flexible and transparent electronic devices.

Hwan Lee, Seung; Lee, Jia; Ho Ra, Chang; Liu, Xiaochi; Hwang, Euyheon [Samsung-SKKU Graphene Center (SSGC), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Department of Nano Science and Technology, SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Sup Choi, Min [Department of Nano Science and Technology, SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Center for Human Interface Nano Technology (HINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Hee Choi, Jun [Frontier Research Laboratory, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Yongin, Gyeonggi-do 446-711 (Korea, Republic of); Zhong, Jianqiang; Chen, Wei [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 (Singapore); Jong Yoo, Won, E-mail: yoowj@skku.edu [Samsung-SKKU Graphene Center (SSGC), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Department of Nano Science and Technology, SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Center for Human Interface Nano Technology (HINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

2014-02-03T23:59:59.000Z

458

Processing and mechanical properties of silicon nitride formed by robocasting aqueous slurries  

SciTech Connect (OSTI)

Robocasting is a new freeform fabrication technique for dense ceramics. It uses robotics to control deposition of ceramic slurries through an orifice. The optimization of concentrated aqueous Si{sub 3}N{sub 4} slurry properties to achieve high green density robocast bodies and subsequent high sintered densities was investigated. The effects of pH, electrolyte, additives and solids loading on the dispersion and rheological properties of Si{sub 3}N{sub 4} slurries were determined. The mechanical behavior of sintered robocast bars was determined and compared to conventionally produced silicon nitride ceramics.

HE,GUOPING; HIRSCHFELD,DEIDRE A.; CESARANO III,JOSEPH

2000-01-26T23:59:59.000Z

459

Titanium nitride thin films deposited by reactive pulsed-laser ablation in RF plasma  

Science Journals Connector (OSTI)

Titanium nitride thin films were deposited on Si (100) substrates by pulsed laser ablation of a titanium target in a N2 atmosphere (gas pressure approx. 10 Pa) using a doubled frequency Nd:YAG laser (532 nm) also assisted by a 13.56-MHz radio frequency (RF) plasma. Deposition was carried out at various substrate temperatures ranging from 373 up to 873 K and films were analyzed by X-ray diffractometry, scanning electron microscopy and optical emission spectroscopy. A comparison between the ‘normal’ pulsed laser deposition (PLD) and the RF plasma-assisted PLD showed the influence of the plasma on the structural characteristics of the thin films.

A. Giardini; V. Marotta; S. Orlando; G.P. Parisi

2002-01-01T23:59:59.000Z

460

A new stepwise-pressing reaction method for synthesizing pure turbostractic boron nitride  

SciTech Connect (OSTI)

A new stepwise-pressing reaction method is proposed, by which pure and near monodisperse turbostractic boron nitride (tBN) nano-particles with high yield (higher than 92%) are selectively synthesized via reacting BBr{sub 3} and (CH{sub 3}){sub 3}N at 260 {sup o}C in benzene. The obtained sample emits a strong photoluminescence band at 346 nm (under a excitation of 215 nm), making tBN a promising candidate for fabricating UV photoelectronic devices.

Yu, Lili; Wang, Tao; Luan, Chunhong [State Key Lab of Crystal Materials, Shandong University, Jinan 250100 (China)] [State Key Lab of Crystal Materials, Shandong University, Jinan 250100 (China); Wang, Qilong [State Key Lab of Crystal Materials, Shandong University, Jinan 250100 (China) [State Key Lab of Crystal Materials, Shandong University, Jinan 250100 (China); School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Cui, Deliang, E-mail: cuidl@sdu.edu.cn [State Key Lab of Crystal Materials, Shandong University, Jinan 250100 (China)] [State Key Lab of Crystal Materials, Shandong University, Jinan 250100 (China)

2010-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Deposition of tungsten nitride on stainless steel substrates using plasma focus device  

Science Journals Connector (OSTI)

Tungsten nitride (WN) films were deposited on the stainless steel-304 substrate by a 2 kJ Mather-type plasma focus device. The preparation method and characterization data are presented. X-ray diffractometer (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed for the characterization of the samples obtained with different number of focus shots, respectively. The average size of crystallites (from XRD), sub-micro-structures (from SEM) and particles (from AFM images) increase when the number of shots increase from 10 to 20 then 30, then they decrease when the substrate is exposed to 40 shots.

G.R. Etaati; M.T. Hosseinnejad; M. Ghoranneviss; M. Habibi; M. shirazi

2011-01-01T23:59:59.000Z

462

Mechanical Instability and Ideal Shear Strength of Transition Metal Carbides and Nitrides  

SciTech Connect (OSTI)

The ideal shear strength of transition metal carbides and nitrides is calculated with the use of the ab initio pseudopotential density functional method. The microscopic mechanism that limits the ideal strength is studied using full atomic and structural relaxation and the results of electronic structure calculations. It is shown that plasticity in perfect crystals can be triggered by electronic instabilities at finite strains. Our study explicitly demonstrates that the ideal strength in these materials is limited by the elastic instability which is in turn initiated by electronic instabilities. The potential application of alloy hardening due to the onset of instabilities at different strains is also discussed.

Jhi, Seung-Hoon; Louie, Steven G.; Cohen, Marvin L.; Morris, J. W.

2001-08-13T23:59:59.000Z

463

CX-010895: Categorical Exclusion Determination  

Broader source: Energy.gov [DOE]

Development and Industrialization of Indium Gallium Nitride/Gallium Nitride (InGaN/GaN) Light Emitting Diodes LEDs on Patterned Sapphire Substrate (PSS) for Low Cost Emitter Architecture CX(s) Applied: B3.6 Date: 06/27/2013 Location(s): California Offices(s): National Energy Technology Laboratory

464

Effects of defect clustering on optical properties of GaN by single and molecular ion irradiation  

SciTech Connect (OSTI)

The effects of irradiation by F, P, and PF{sub 4} on optical properties of GaN were studied experimentally and by atomistic simulations. Additionally, the effect of Ag was studied by simulation. The irradiation energy was 0.6?keV/amu for all projectiles. The measured photoluminescence (PL) decay time was found to be decreasing faster when irradiation was done by molecular ion compared to light ion irradiation. The PL decay time change is connected with the types of defect produced by different projectiles. Simulation results show that the light ions mainly produce isolated point defects while molecular and heavy ions produce clusters of point defects. The total amount of defects produced by the PF{sub 4} projectile was found to be very close to the sum of all defects produced in five individual cascades started by one P and four F single ions. This and the similar depth profiles of damage produced by molecular and light ion irradiations suggest that the defect clusters are one of the important reasons for fast PL decay. Moreover, the simulations of irradiation by Ag ions, whose mass is close to the mass of the PF{sub 4} molecule, showed that the produced defects are clustering in even bigger conglomerates compared to PF{sub 4} case. The latter has a tendency to split in the pre-surface region, reducing on average the density of the collision cascade.

Ullah, M. W., E-mail: mohammad.ullah@helsinki.fi; Kuronen, A.; Nordlund, K.; Djurabekova, F. [Department of Physics, University of Helsinki, P.O. Box 64, FIN 00014 (Finland); Karaseov, P. A.; Karabeshkin, K. V.; Titov, A. I. [Department of Physical Electronics, St. Petersburg State Polytechnic University, St. Petersburg (Russian Federation)

2013-11-14T23:59:59.000Z

465

Neutron-transmuted carbon-14 in neutron-irradiated GaN: Compensation of DX-like center  

SciTech Connect (OSTI)

The transmuted-C related luminescence and net carrier concentration are studied by combining photoluminescence, liquid scintillation, and Raman scattering. GaN single crystal films grown by metalorganic-vapor-phase epitaxy are irradiated with fast and thermal neutrons at fluxes of 3.9 × 10{sup 13} cm{sup ?2}s{sup ?1} and 8.15 × 10{sup 13} cm{sup ?2}s{sup ?1}, respectively. Irradiation time is 48 hours. The calculated {sup 72}Ge and {sup 14}C concentrations are 1.24 × 10{sup 18} cm{sup ?3} and 1.13 × 10{sup 18} cm{sup ?3}, respectively. The transmuted {sup 14}C is detected by the liquid scintillation method to survey ?-rays emitted in the process of {sup 14}C decays from {sup 14}N. Tritium ({sup 3}H) is also emitted by a (n,t) reaction of {sup 14}N due to the neutron irradiation above 4.5 MeV. Photoluminescence relating to C, DX-like center of Ge and yellow luminescence band are observed in 1000 °C annealed NTD-GaN. The free electron concentration estimated from Raman scattering is 4.97 × 10{sup 17} cm{sup ?3}. This value is lower than that from the transmuted Ge concentration, suggesting the compensation due to the transmuted {sup 14}C acceptors.

Ida, T.; Oga, T.; Kuriyama, K. [College of Engineering and Research Center of Ion Beam Technology, Hosei University Koganei, Tokyo 184-8584 (Japan); Kushida, K. [Departments of Arts and Sciences, Osaka Kyoiku University Kashiwara, Osaka 582-8582 (Japan); Xu, Q.; Fukutani, S. [Research Reactor Institute, Kyoto University Kumatori, Osaka 590-0494 (Japan)

2013-12-04T23:59:59.000Z

466

Quantitative description of microstructure defects in hexagonal boron nitrides using X-ray diffraction analysis  

SciTech Connect (OSTI)

A routine for simultaneous quantification of turbostratic disorder, amount of puckering and the dislocation and stacking fault density in hexagonal materials was proposed and tested on boron nitride powder samples that were synthesised using different methods. The routine allows the individual microstructure defects to be recognised according to their effect on the anisotropy of the X-ray diffraction line broadening. For quantification of the microstructure defects, the total line broadening is regarded as a linear combination of the contributions from the particular defects. The total line broadening is obtained from the line profile fitting. As testing material, graphitic boron nitride (h-BN) was employed in the form of hot-isostatically pressed h-BN, pyrolytic h-BN or a h-BN, which was chemically vapour deposited at a low temperature. The kind of the dominant microstructure defects determined from the broadening of the X-ray diffraction lines was verified by high resolution transmission electron microscopy. Their amount was attempted to be verified by alternative methods. - Highlights: • Reliable method for quantification of microstructure defects in BN was suggested. • The method is based on the analysis of anisotropic XRD line broadening. • This XRD line broadening is unique and characteristic of the respective defect. • Thus, the quantification of coexistent microstructure defects is possible. • The method was tested on hexagonal BN, which was produced by different techniques.

Schimpf, C., E-mail: schimpf@iww.tu-freiberg.de; Motylenko, M.; Rafaja, D.

2013-12-15T23:59:59.000Z

467

Ferromagnetism in Doped Thin-Film Oxide and Nitride Semiconductors and Dielectrics  

SciTech Connect (OSTI)

The principal goal in the field of high-Tc ferromagnetic semiconductors is the synthesis, characterization and utilization of semiconductors which exhibit substantial carrier spin polarization at and above room temperature. Such materials are of critical importance in the emerging field of semiconductor spintronics. The interaction leading to carrier spin polarization, exchange coupling between the dopant spins and the valence or conduction band, is known to be sufficiently weak in conventional semiconductors, such as GaAs and Si, that magnetic ordering above cryogenic temperatures is essentially impossible. Since the provocative theoretical predictions of Tc above ambient in p-Mn:ZnO and p-Mn:GaN (T. Dietl et al., Science 287 1019 (2000)), and the observation of room-temperature ferromagnetism in Co:TiO2 anatase (Y. Matsumoto et al., Science 291 854 (2001)), there has been a flurry of work in oxides and nitrides doped with transition metals with unpaired d electrons. It has even been claimed that room-temperature ferromagnetism can be obtained in certain d0 transition metals oxides without a dopant. In this Report, the field of transition metal doped oxides and nitrides is critically reviewed and assessed from a materials science perspective. Since much of the field centers around thin film growth, this Report focuses on films prepared not only by conventional vacuum deposition methods, but also by spin coating colloidal nanoparticles.

Chambers, Scott A.

2006-10-01T23:59:59.000Z

468

Surface modification by gas nitriding for improving cavitation erosion resistance of CP-Ti  

Science Journals Connector (OSTI)

Abstract Gas nitriding process has been used to increase the surface hardness of titanium, in this study we used this technique to improve the cavitation erosion resistance (Rce) of commercial purity titanium (CP-Ti). We also studied microstructure, phase constituents, hardness and the effect of processing parameters on Rce of the treated samples. The results indicated that the Rce of the treated samples was related to the processing parameters. The sample treated at 850 °C for 4 h has the highest Rce, which was attributed to the compound layer (CL) with a hard, dense and free-defects microstructure. With increasing the nitriding temperature and duration, the Rce of the treated samples decreased due to the excessive oxide and defects formed in the CL. When the CL was removed, the treated sample exhibited an excellent cavitation erosion behavior. It was supposed to be due to the existence of the residual compressive stresses field in the nitrogen diffusion zone, which played an important role in preventing microcracks initiation and propagation to interior for cavitation damage.

Haibin Li; Zhenduo Cui; Zhaoyang Li; Shengli Zhu; Xianjin Yang

2014-01-01T23:59:59.000Z

469

Hort-Range Wetting at Liquid Gallium-Bismuth Alloy Surfaces: X-ray Measurements and Square-Gradient Theory  

SciTech Connect (OSTI)

We present an x-ray reflectivity study of wetting at the free surface of the binary liquid metal alloy gallium-bismuth (Ga-Bi) in the region where the bulk phase separates into Bi-rich and Ga-rich liquid phases. The measurements reveal the evolution of the microscopic structure of the wetting films of the Bi-rich, low-surface-tension phase along several paths in the bulk phase diagram. The wetting of the Ga-rich bulk's surface by a Bi-rich wetting film, the thickness of which is limited by gravity to only 50 Angstroms, creates a Ga-rich/Bi-rich liquid/liquid interface close enough to the free surface to allow its detailed study by x rays. The structure of the interface is determined with Angstromsngstrem resolution, which allows the application of a mean-field square gradient model extended by the inclusion of capillary waves as the dominant thermal fluctuations. The sole free parameter of the gradient model, the influence parameter K, that characterizes the influence of concentration gradients on the interfacial excess energy, is determined from our measurements. This, in turn, allows a calculation of the liquid/liquid interfacial tension, and a separation of the intrinsic and capillary wave contributions to the interfacial structure. In spite of expected deviations from MF behavior, based on the upper critical dimensionality (Du = 3 ) of the bulk, we find that the capillary wave excitations only marginally affect the short-range complete wetting behavior. A critical wetting transition that is sensitive to thermal fluctuations appears to be absent in this binary liquid-metal alloy.

Huber, P.; Shpyrko, O; Pershan, P; Ocko, B; DiMasi, E; Deutsch, M

2009-01-01T23:59:59.000Z

470

Z .Surface and Coatings Technology 127 2000 260 265 Characterization of carbon nitride thin films deposited by  

E-Print Network [OSTI]

-screw adapter and monitored by measuring the back reflection power at the end of a water load. A mixture polycrystalline car- bon nitride films, and the resulting mechanical proper- ties are not as good as predicted a valve between the deposition chamber and the vacuum pumps. The microwave power was adjusted by a four

Gao, Hongjun

471

Power mixture and green body for producing silicon nitride base & articles of high fracture toughness and strength  

DOE Patents [OSTI]

A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength. The powder mixture includes 9a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon mitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12m.sup.2 g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified articel an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder.

Huckabee, Marvin L. (Marlboro, MA); Buljan, Sergej-Tomislav (Acton, MA); Neil, Jeffrey T. (Acton, MA)

1991-01-01T23:59:59.000Z

472

Theoretical study on interaction of hydrogen with single-walled boron nitride nanotubes. II. Collision, storage, and adsorption  

E-Print Network [OSTI]

of a true hydrogen storage capacity, thus it would be also true that some results of rather high storage storage material or not. Our previous study6 showed that the pristine CNT is not an effective hydrogenTheoretical study on interaction of hydrogen with single-walled boron nitride nanotubes. II

Goddard III, William A.

473

Coating of Titanium Nitride on Stainless Steel Targets by a 4 kJ Plasma Focus Device  

Science Journals Connector (OSTI)

Titanium nitride thin films were deposited on stainless steel (SS316L) targets by using a 4 kJ plasma focus device. The corresponding energy flux delivered to...13 kev cm?3 ns?1. X-ray diffraction analysis reveal...

M. Omrani; M. Habibi; R. Amrollahi

2012-08-01T23:59:59.000Z

474

First-Principles Study of MetalCarbide/Nitride Adhesion: Al/VC vs. Al/VN Donald J. Siegel  

E-Print Network [OSTI]

-oxide ce- ramics. Within this class, the transition metal carbides and ni- trides are a particularly knowledge, there have been only three studies of adhesion between metals and transition metal carbidesFirst-Principles Study of MetalĀ­Carbide/Nitride Adhesion: Al/VC vs. Al/VN Donald J. Siegel

Adams, James B

475

Ion exchange separation of plutonium and gallium (1) resource and inventory requirements, (2) waste, emissions, and effluent, and (3) facility size  

SciTech Connect (OSTI)

The following report summarizes an effort intended to estimate within an order-of-magnitude the (1) resource and inventory requirements, (2) waste, emissions, and effluent amounts, and (3) facility size, for ion exchange (IX) separation of plutonium and gallium. This analysis is based upon processing 3.5 MT-Pu/yr. The technical basis for this summary is detailed in a separate document, {open_quotes}Preconceptual Design for Separation of Plutonium and Gallium by Ion Exchange{close_quotes}. The material balances of this separate document are based strictly on stoichiometric amounts rather than details of actual operating experience, in order to avoid classification as Unclassified Controlled Nuclear Information. This approximation neglets the thermodynamics and kinetics which can significantly impact the amount of reagents required. Consequently, the material resource requirements and waste amounts presented here would normally be considered minimums for processing 3.5 MT-Pu/yr; however, the author has compared the inventory estimates presented with that of an actual operating facility and found them similar. Additionally, the facility floor space presented here is based upon actual plutonium processing systems and can be considered a nominal estimate.

DeMuth, S.

1997-09-30T23:59:59.000Z

476

Heteroepitaxial growth and surface structure of L1{sub 0}-MnGa(111) ultra-thin films on GaN(0001)  

SciTech Connect (OSTI)

L1{sub 0}-structured MnGa(111) ultra-thin films were heteroepitaxially grown on GaN(0001) under lightly Mn-rich conditions using molecular beam epitaxy. Room-temperature scanning tunneling microscopy (STM) investigations reveal smooth terraces and angular step edges, with the surface structure consisting primarily of a 2 × 2 reconstruction along with small patches of 1 × 2. Theoretical calculations were carried out using density functional theory, and the simulated STM images were calculated using the Tersoff-Hamman approximation, revealing that a stoichiometric 1 × 2 and a Mn-rich 2 × 2 surface structure give the best agreement with the observed experimental images.

Mandru, Andrada-Oana; Wang, Kangkang; Cooper, Kevin; Ingram, David C.; Smith, Arthur R. [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States)] [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States); Garcia Diaz, Reyes; Takeuchi, Noboru [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States) [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States); Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada Baja California, Codigo Postal 22800 (Mexico); Haider, Muhammad [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States) [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States); Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran, 31261 (Saudi Arabia)

2013-10-14T23:59:59.000Z

477

Room-temperature high radio-frequency source power effects on silicon nitride films deposited by using a plasma-enhanced chemical vapor deposition  

Science Journals Connector (OSTI)

Silicon nitride films were deposited at room temperature using a plasma-enhanced chemical vapor deposition system. In this study, the effects of radio frequency (RF) source power ranging from 200 W to ... charact...

Byungwhan Kim; Suyeon Kim

2008-10-01T23:59:59.000Z

478

An Investigation of the Properties of Silicon Nitride (SiNx) Thin Films Prepared by RF Sputtering for Application in Solar Cell Technology  

Science Journals Connector (OSTI)

Silicon nitride films deposited on glass and multicrystalline silicon by RF sputtering with power between 100–350W. The target was hot pressed Si3N4 ceramic. The morphology and optical properties of films are inv...

Negin Manavizadeh; Alireza Khodayari…

2009-01-01T23:59:59.000Z

479

Two-dimensional excitons in three-dimensional hexagonal boron nitride  

SciTech Connect (OSTI)

The recombination processes of excitons in hexagonal boron nitride (hBN) have been probed using time-resolved photoluminescence. It was found that the theory for two-dimensional (2D) exciton recombination describes well the exciton dynamics in three-dimensional hBN. The exciton Bohr radius and binding energy deduced from the temperature dependent exciton recombination lifetime is around 8?Å and 740?meV, respectively. The effective masses of electrons and holes in 2D hBN deduced from the generalized relativistic dispersion relation of 2D systems are 0.54m{sub o}, which are remarkably consistent with the exciton reduced mass deduced from the experimental data. Our results illustrate that hBN represents an ideal platform to study the 2D optical properties as well as the relativistic properties of particles in a condensed matter system.

Cao, X. K.; Lin, J. Y., E-mail: hx.jiang@ttu.edu; Jiang, H. X., E-mail: jingyu.lin@ttu.edu [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States); Clubine, B.; Edgar, J. H. [Department of Chemical Engineering, Kansas State University, Manhattan, Kansas 66506 (United States)] [Department of Chemical Engineering, Kansas State University, Manhattan, Kansas 66506 (United States)

2013-11-04T23:59:59.000Z

480

Plasma-enriched chemical vapor deposition of silicon nitride on silicon carbide fibers  

SciTech Connect (OSTI)

Near stoichiometric Si:N coatings were deposited by means of PECVD on SCS-6 SiC fibers which contained a carbon-rich coating. Weight loss associated with oxidation of the outer carbon-rich coating of the as-received SiC fibers was greatly reduced for the Si:N coated SiC fibers even after 10 h heat-treatment in oxygen at 800{degrees}C. Auger Electron Spectroscopy (AES) was used to obtain elemental compositions of the as-received and Si:N coated SiC fibers after heat-treatment. Negligible amounts of oxygen were found at the carbon-rich coating of the heat-treated Si:N coated SiC fiber. These results clearly prove the effectiveness of PECVD silicon nitride coating as an oxygen diffusion barrier.

Stinespring, C.D.; Collazos, D.F.; Gupta, R.K. [West Virginia Univ., Morgantown, WV (United States)] [and others

1994-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "gallium nitride gan" from the National Library of EnergyBeta (NLEBeta).
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481

Dilute Group III-V nitride intermediate band solar cells with contact blocking layers  

DOE Patents [OSTI]

An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (V.sub.OC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.

Walukiewicz, Wladyslaw (Kensington, CA); Yu, Kin Man (Lafayette, CA)

2012-07-31T23:59:59.000Z

482

Interaction and charge transfer in the iron nitride Fe4N  

Science Journals Connector (OSTI)

The linearized augmented-plane-wave method has been used to calculate the electronic bands of the cubic iron nitride Fe4N. Strong interaction between N 2p and Fe 4s orbitals of nearest Fe atoms (FeII has been revealed. This interaction leads to an increase in the N 2p population. The Fe 3d bands remain almost the same as in the pure Fe metal with negligible interaction with neighboring N orbitals. However, the occupation of the FeII 3d bands and the total number of electrons of FeII atoms increases due to less screening. This unified picture clarifies the controversy in the previous explanations of the experimental results obtained from magnetic measurements, electron diffraction, and photoelectron spectroscopy.

Wei Zhou, Li-jia Qu, Qi-ming Zhang, and Ding-sheng Wang

1989-09-15T23:59:59.000Z

483

Electrical transport properties of Si-doped hexagonal boron nitride epilayers  

SciTech Connect (OSTI)

The suitability of Si as an n-type dopant in hexagonal boron nitride (hBN) wide bandgap semiconductor has been investigated. Si doped hBN epilayers were grown via in-situ Si doping by metal organic chemical vapor deposition technique. Hall effect measurements revealed that Si doped hBN epilayers exhibit n-type conduction at high temperatures (T > 800 K) with an in-plane resistivity of ?12 ?·cm, electron mobility of ? ? 48 cm{sup 2}/V·s and concentration of n ? 1 × 10{sup 16} cm{sup ?3}. Temperature dependent resistivity results yielded a Si energy level in hBN of about 1.2 eV, which is consistent with a previously calculated value for Si substitutionally incorporated into the B sites in hBN. The results therefore indicate that Si is not a suitable dopant for hBN for room temperature device applications.

Majety, S.; Doan, T. C.; Li, J.; Lin, J. Y.; Jiang, H. X., E-mail: hx.jiang@ttu.edu [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX 79409 (United States)

2013-12-15T23:59:59.000Z

484

Molybdenum nitride/nitrogen-doped graphene hybrid material for lithium storage in lithium ion batteries  

Science Journals Connector (OSTI)

Abstract Molybdenum nitride and nitrogen-doped graphene nanosheets (MoN/GNS) hybrid materials are synthesized by a simple hydrothermal method combined with a heat treatment at 800 °C under an ammonia atmosphere. It is found by scanning and transmission electron microscopy that MoN nanoparticles ranging from 20 to 40 nm in diameter are homogeneously anchored to GNS. The electrochemical performance of MoN/GNS as a possible anode material for Li-ion batteries is investigated. Galvanostatic charge/discharge experiments reveal that the hybrid materials exhibit an enhanced lithium storage capacity and excellent rate capacity as a result of its efficient electronic and ionic mixed conducting network. The electrochemical results demonstrate that the weight ratio of GNS and MoN had significant effect on the electrochemical performance.

Botao Zhang; Guanglei Cui; Kejun Zhang; Lixue Zhang; Pengxian Han; Shanmu Dong

2014-01-01T23:59:59.000Z

485

Graphene on boron-nitride: Moiré pattern in the van der Waals energy  

SciTech Connect (OSTI)

The spatial dependence of the van der Waals (vdW) energy between graphene and hexagonal boron-nitride (h-BN) is investigated using atomistic simulations. The van der Waals energy between graphene and h-BN shows a hexagonal superlattice structure identical to the observed Moiré pattern in the local density of states, which depends on the lattice mismatch and misorientation angle between graphene and h-BN. Our results provide atomistic features of the weak van der Waals interaction between graphene and BN which are in agreement with experiment and provide an analytical expression for the size of the spatial variation of the weak van der Waals interaction. We also found that the A-B-lattice symmetry of graphene is broken along the armchair direction.

Neek-Amal, M. [Department of Physics, University of Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium); Department of Physics, Shahid Rajaee University, Lavizan, Tehran 16788 (Iran, Islamic Republic of); Peeters, F. M. [Department of Physics, University of Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)

2014-01-27T23:59:59.000Z

486

Thermal interface conductance across a graphene/hexagonal boron nitride heterojunction  

SciTech Connect (OSTI)

We measure thermal transport across a graphene/hexagonal boron nitride (h-BN) interface